Modern Concept Science and Technology 10

Approved by the Government of Nepal, Ministry of Education, Curriculum Development Centre, Sanothimi, Bhaktapur as an additional material for schoolAuthorsChinta Mani PantheeM.Sc., B.Ed., Ph.D.Lok Bahadur ThamsuhangM.Sc., M.Ed.Kamal NeupaneM.Sc.10

Published by:Nova Publication Pvt. Ltd.Satungal, KathmanduTel.: 01-4313205www.novapublication.com.npAuthor:Chinta Mani PantheeLok Bahadur ThamsuhangKamal NeupaneEdition:Fifth - 2080Sixth Revised : 2081Reprint : 2082Copyright:Chinta Mani PantheePrice : Rs. 667 /–Print Quantity : 10,000Layout and Design:Zeeta Computer Service Ptv.Ltd.Printed in Nepal10

PREFACEModern Concept Science and Technology for grade 10 is written to meet the objectives of the curriculum of class 10 science and technology developed by CDC (Curriculum Development Center), Sanothimi, Bhaktapur. This edition of our textbook meets the criteria of basic knowledge in science and technology for students who study in class 10. It will help students to achieve the goals of life by gaining of knowledge, skills and values in Science and technology.Logical placing of key points and well organized matter are given high priority throughout the textbook. Appropriate pictures, matter in simplified language and organization of the content with new features are our high expectation values about popularity of this textbook among the readers.Features of Modern Concept Science and TechnologyA notable concern of many teachers is to follow a well-organized textbook with step by step learnings in a continuous flow. The organization of this textbook is logically designed to make the book's information more accessible.1. Top of the first page, just below about the scientist of each unit consists of syllabus issued by CDC (Curriculum Development Center), Sanothimi, Bhaktapur for class 10.2. Top of the first page of each unit consists about the scientist of the related topic. It inspires and motivates the students towards the scientific skill.3. The most important idea of writing terms and terminologies on the first page of each unit is devoted to screen out the main content to be covered.4. Highlighted definitions, catchy memory tips and bubble box on pages inside of a chapter for a quick look on important points to be remembered are provided in the first page of each unit.5. Activities and solved numerical problems are given in each unit of the same page with corresponding to the topic to develop the scientific skill in the readers.6. Higher Order Thinking Skill of Knowledge, Understanding, Application, and Higher Ability with their answer are given at the end of each unit under the title HOT Skill to get idea to solve the questions given in the three steps exercise.7. This text book focuses primarily on all three level questions to test students' skill under the title three steps exercise.With these all features in a well-organized content, the central focus of this book is to encourage students and make the text user-friendly for all. The HOT skill and three levels grid based exercise will help teachers to set test papers for assessments. Students' interest will be peaked when they will find the screen out terms and terminologies, the appropriate pictures and key points throughout the textbook. We hope that this book will help teaching in learner-centered way.We wish to express our sincere gratitude to Mr. Megh Raj Poudel, Managing director of Nova Publication Pvt. Ltd. for publishing this book. Similarly, thanks are due to Mr. Deepak Bahadur Bista, Ashim (Indra) Rijal, Deepak Banjade, Dilip Belbase and Srijan Adhikari for their valuable help during the preparation and content editing of the book. Likewise, thanks are due to Mr. Jagadish Pokhrel for his praiseworthy language editing.Finally, we owe full responsibility of misprints and other technical errors, if any, found in this textbook in spite of our best effort to make this book error-free. Constructive criticism and suggestions for improvement of this book will be highly appreciated.AuthorsKathmandu, Nepal

1 Scientific Study 1-142 Classification of Living Things 15-473 Life cycle of Honey Bee 48-614 Heredity 62-1115 Physiological Structure and Life Process 112-1456 Nature and Environment 146-1647 Force and Motion 165-1938 Pressure 194-2149 Heat Energy 215-23610 Wave 237-28811 Electricity and Magnetism 289-31012 Universe 311-32513 Information and Communication Technology 326-34514 Classification of Elements 346-36615 Chemical Reaction 367-37916 Some Gases 380-39917 Metals 400-41318 Hydrocarbons and Its Compounds 414-43019 Chemicals Used in Daily Life 431-450Table of Contents

PB <Running HeadeR> Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 1Key terms and terminologies of the unit1. Variables : The factors, traits or conditions that are considered during an experiment are called variables. 2. Independent variable : The variable whose value can be changed by the scientist during his experiment is called independent variable. 3. Dependent variable : The variable whose value depends upon the value of other variables is called dependent variable.4. Controlled variable : The variable which is kept constant during the experiment is called controlled variable.5. Physical quantities : The quantities which can be measured by using different kinds of physical devices are called physical quantities. 6. Measurement : The comparison of any unknown physical quantity with its standard unit is called measurement. 7. Unit : The standard known quantity which is used to measure the unknown quantity of the same kind is called unit.8. SI units : The General Conference of Weights and Measures held in Paris, France in 1960 introduced a new system of units known as international system of units (SI units). 9. Fundamental quantities : The physical quantities which are independent from other quantities are called fundamental quantities.10. Derived quantities : The physical quantities which are based on the fundamental quantities are called derived quantities. 11. Fundamental units : The units which are independent from other units are called fundamental units.Sequence of Curriculum Issued by CDC Variables of scientific research: independent variables, dependent variables and controlled variables Importance of controlled variables Fundamental and derived units: introduction and examples, units involved in derived units, unitwise analysis of equationUNITScientific Study1Estimated teaching periods Theory Practical4 1Lujendra Ojha, born in Nepal in 1990, is a distinguished planetary scientist celebrated for his significant contributions to the field. He gained widespread recognition for his pivotal role in uncovering evidence indicating the existence of liquid water on Mars. This ground-breaking discovery defied conventional beliefs about the Martian landscape and offered valuable perspectives on its potential for supporting life. Ojha's work continues to inspire further exploration and understanding of our neighbouring planet. Lujendra OjhaAbout the Nepalese Scientist

2 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 312. Derived units : The units which are derived from the combination of two or more fundamental units are called derived units. 13. Unit-wise analysis : The study of the relationship between physical equations with the help of units of measurement is called unit-wise analysis. 14. Principle of homogeneity : The principle of homogeneity states that an equation is unit-wise correct if the units of the various terms on either side of the equation are the same. IntroductionSometimes we feel cold and sometimes we feel hot. Is it cold or hot today? Why does it happen? It may be due to sunlight, climate or weather condition. To know its exact reason, it is necessary to study each factor one by one. It is called scientific study.Scientific study is a systematic way of learning about nature and its phenomena. It involves observation, asking a question, formation of a hypothesis, conducting an experiment, collection of data, analysis of data, drawing conclusion and making a valuable report. Scientific study always depends on well-planned experiment that gives valuable result. Each scientific experiment is affected by several factors. These factors are called variables. VariablesACTIVITY 1Let’s suppose we are going to find the relation between the area of the rectangle with its length and breadth. The rectangle has length, breadth and area. The area of the rectangle is dependent upon the length and the breadth of the rectangle. If we change length and breadth together, the area will also change. However, we would not know if the area changed due to a change in the length or due to a change in the breadth. We would also not know if the area is directly proportional or inversely proportional to the length or breadth. So, for accuracy, let’s keep the magnitude of the breadth constant so that it will not affect the experiment. Let’s change the magnitude of the length multiple times. Whenever the value of the length is changed the value of the area keeps changing. When length is increased the area increases. If the magnitude of length is decreased the area also decreases. In this activity, the area, the length and the breadth are some factors, that are being considered. Such factors are called variables. The factors, conditions and traits that are considered during the experiment are called variables. To increase the accuracy of the experiment and to construct a clear relation between area and length, the breadth was kept constant throughout the experiment. So, the breadth is a controlled variable. The variables whose value is kept constant throughout the experiment are called controlled variables. To find out the relation between the area and the length, the length was changed by us multiple times. So, the length is an independent variable. The variables whose value can be changed by us freely are called independent variables. MEMORY TIPSThe systematic and practical study of the structure and behaviour of the natural and physical world is called science.

2 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 3The magnitude of the area changed when the length was changed. The area was dependent upon the magnitude of the length. So, it is called the dependent variable. The variables whose value is dependent upon the independent variables are called dependent variables. Examples of activities where we discuss different variables a. If we have to collect a bucket of water from the tap, we have to rotate the tap spindle. If the tap spindle is rotated more, more water will come out of the tap. If the tap spindle is rotated less, less water will come from the tap. Here, the rotation of the spindle is the independent variable, the amount of water is the dependent variable and the size of the tap is the controlled variable. b. If we see an earthworm in the field at night and use a torch light to see it, we can notice that it runs away from the light. If we use a brighter torch it will try to escape faster. Here, the intensity of the light is an independent variable because we change it. Negative phototaxis, the act of running away from light shown by the earthworm is the dependent variable and the temperature of the environment and soil are the controlled variable. c. If the bicycle runs faster, the brightness of the bulb will increase. Here the rate of rotation or the speed of the bicycle is an independent variable because it can be changed by us. The brightness of a bulb is a dependent variable because it depends upon the speed of the bicycle. The size of the dynamo, the distance between the coil and magnet etc are controlled variables. d. Let’s suppose we are going to make a tea. The sugar dissolves less in cold water but if we increase the temperature more sugar will be dissolved. From this, we can say that the temperature of water is an independent variable which can be changed by us. The solubility of the sugar is a dependent variable because it responds to the change in temperature. The amount of water is a controlled variable. e. If we are making an electromagnet, we need an insulated copper coil, iron nail and batteries. It is found that when one battery of 1.5 volts is used a weak magnetic field is formed. If we use two cells to supply 3 volts of emf from the same solenoid, a stronger magnetic field is produced. From this, we can conclude that the emf of the battery is the independent variable, the strength of the magnetic field is the dependent variable and the number of turnings of the solenoid and its size are controlled variables. f. If we take two identical vitamin C tablets, break the first one into powder and put it in 100 ml water of water. Then put another tablet as a whole in another 100 ml of water. We can see that the powdered one will dissolve faster in the water. Here, the surface area of vitamin C is the independent variable, the rate of dissolving or reaction is the dependent variable and the amount of water and temperature of water are controlled variables.g. If we put two identical seedlings into two identical pots with the same amount of soil, fertilizer and water and put one of them in a closed dark room and another one in sunny fields, after a week we can see that the plant put in the sunny field will grow better and taller than the one put in the dark room. Here, the amount of sunlight is an independent variable, the growth of the plant is the dependent variable and the soil, the fertilizer, the water etc are controlled variables. h. During sports day, if a student has to run 100 m, they have to run faster and reach the goal earlier than another student. Provided that all students have the same weight and height and are healthy, the students who finish the race faster have a faster heartbeat and the student who finishes the race later has a slower heartbeat. Here, the duration they used to complete the race is an independent variable. The heart rate is a dependent variable. Their physical condition, length of track etc are controlled variables.

4 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 5i. If a person has made a rubber catapult and paper bullets for it, a catapult can be used to shoot paper bullets. If the rubber of the catapult is stretched longer, the paper bullet can reach farther. If the rubber of the catapult is stretched shorter, the paper bullet cannot reach farther. So, the increase in the length of rubber is an independent variable because we can change it. The length covered by the paper bullet is a dependent variable because it depends upon the change in the length of the rubber. The rubber itself, the catapult, the mass of the paper bullet and the size of the paper bullet are kept constant. So, they are controlled variables. j. If we connect a 10 cm long wire to a 9-volt battery to glow an LED bulb it glows well. If we use a 100 cm long wire to a 9-volt battery to glow the same LED bulb it glows dimly. Here the length of the wire is an independent variable, the brightness of the bulb is a dependent variable and the thickness of the wire, voltage of the battery and power of the LED bulb are controlled variables. As discussed in the above experiments, we can conclude that there are always some variables in the experiments. They are considered during the experiment. The variables are mostly represented using symbols. The variables can be broadly classified into three categories. They are independent variables, dependent variables and controlled variables. Other names of independent variableAs we discussed above there are some factors in the experiment that are changed by scientists. They are the causative factors. When these factors are changed, some other variable will automatically change. These causative factors are independent variables. Independent variables are kept on the right-hand side of the equation. Therefore, they are also called right variables. If the relation between the independent variable and dependent variable is plotted in a graph, the independent variables are kept in the x-axis. Therefore, the independent variables are called x-variables. Since the x-axis is a horizontal line, the independent variables kept in the x-axis are also called horizontal variables. An experiment has only one independent variable. If multiple independent variables are present in the same experiment, it will be very difficult to establish the relation between the dependent variable and the independent variable. FACTS WITH REASONSDuring the laboratory preparation of carbon dioxide by dissolving calcium carbonate in hydrochloric acid, the reaction was faster when powdered calcium carbonate was used and the reaction was slower when a cubical piece of calcium carbonate was put in dilute hydrochloric acid. Here surface area is considered the independent variable and rate of reaction is considered the dependent variable. Give reason.During the production of carbon dioxide by dissolving calcium carbonate in dilute hydrochloric acid, the surface area is considered an independent variable because we can change it continuously. Here, the rate of reaction is called the dependent variable because it depends upon the change in the surface area of the limestone. Other names of dependent variableAs we discussed above there are factors in the experiment that respond to the changes in independent variables. Whenever the researchers change the magnitude of the independent variable, there is always another variable that changes as an effect. Those variables are called dependent variables. They are kept on the left side of the equation. Hence, they are called left variables. If the relation between the independent variable and dependent variable is plotted

4 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 5in the graph, the dependent variable is kept in the y-axis. So, the dependent variable is also called the y-variable. Since the y-axis is vertical, the dependent variables kept in the y-axis are also called vertical variables. There is always one dependent variable per experiment. If multiple dependent variables are present in the same experiment, it will be very difficult to establish the relation between the dependent variable and the independent variable. Controlled VariableAs we discussed above, there can be many variables in an experiment. It will be difficult to establish a clear relationship between dependent variables and independent variables if there are many independent variables. It might make the result unreliable. Therefore, we should select one dependent variable and one independent variable. Besides that, every other variable must be kept constant throughout the experiment. They are called controlled variables. They are kept constant so that they would not affect the relation between the dependent and independent variables. There are one or more controlled variables in an experiment. The controlled variable always remains constant so it is not plotted in the graph but mentioned as constant. The graph is only used to see and compare the changes in dependent variables when there is a change in the independent variable. MeasurementMeasurement is an essential process for the accurate description of various quantities. For example, one should know the measurement of the quantity of matter in a body to describe its exact mass. In our daily life, measurement of distance, time and mass is necessary. These measurable quantities are called physical quantities. Thus, the quantities which can be measured by using different kinds of physical devices are called physical quantities. For example, mass, length, time, volume, force, density, temperature, work, energy, power, speed, etc. The process of measurement is basically a comparison process. In order to measure a physical quantity, we assume a certain magnitude of the quantity as a standard called unit. Thus, measurement is the comparison of an unknown physical quantity with a known standard quantity of the same kind.UnitThe standard known quantity which is used to measure the unknown quantity of the same kind is called unit. The unit is a fixed quantity. It is used to measure other quantities of the same kind. For example, one unit of length is assumed as the distance between two parallel gold lines on a platinum-iridium rod which is preserved at 0°C and standard atmospheric pressure. It is kept in the international bureau of weight and measures at Sevres, near Paris, France.MEMORY TIPSIf we want to increase the accuracy of the experiment, if we want to know the exact relation between a dependent variable and an independent variable, we should repeat the same experiments many times. We should do it at least three times or more. MEMORY TIPSNepal Bureau of Standard and Metrology (NBSM) at Balaju, Kathmandu is the National Standard Body of Nepal.Measuring length Weighing

6 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 7Classification of Physical Quantities and UnitsIn physics, there are a number of physical quantities to be measured. It is difficult to define a new unit for each of them as well as to remember a large number of new units. Most of the physical quantities are inter-related. For example, velocity is expressed as displacement upon time. So the unit of velocity is expressed in terms of unit of displacement and time. But all the physical quantities are not independent. Some are independent and others are dependent (derived). On the basis of this fact, the physical quantities are classified as:A) Fundamental physical quantitiesB) Derived physical quantitiesA) Fundamental physical quantitiesThose physical quantities which are independent of each other are called fundamental physical quantities. Length, mass, time, temperature, electric current, amount of substance and luminous intensity are the seven fundamental physical quantities. Other physical quantities can be obtained from them. B) Derived physical quantitiesThose physical quantities which are derived from the fundamental physical quantities are called derived physical quantities. For example: area, volume, velocity, force, speed, work, power, pressure, etc. i) Area is expressed as the product of length and breadth i.e. Area = length × breadthii) Volume is expressed as the product of length, breadth and height i.e. Volume = length × breadth × heightiii) Density is expressed as mass upon volume i.e. Density = massvolume , etc.FACTS WITH REASONSVelocity is a derived physical quantity. Why?Here, Velocity = displacementtime taken = lengthtime takenVelocity is formed by the combination of two fundamental quantities, i.e. length and time. So, it is a derived physical quantity.There are two types of units. They are fundamental units and derived units.a) Fundamental unitsThe physical quantities which are independent from other quantities are called fundamental quantities. For examples, metre (m), kilogram (kg), second (s), kelvin (K), etc. There are seven fundamental physical quantities. To measure these seven fundamental physical quantities, there are seven fundamental units. They are metre (m), kilogram (kg), second (s), kelvin (K), ampere (A), candela (Cd) and mole (mol.).MEMORY TIPSThe magnitude of 1 second is same all over the world because it is well defined standard unit.

6 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 7In SI System, the seven fundamental physical quantities and their units are as follows:S.N Fundamental Quantity SI units SI Symbol1. Mass kilogram kg2. Length metre m3. Time second s4. Temperature kelvin K5. Electric current ampere A6. Amount of substance mole mol.7. Luminous intensity candela cdb) Derived unitsThere are many units which are expressed in terms of fundamental units. They are called derived units. For example, m2, m3, m/s, N, Pa. Thus, those units which are formed by the combination of two or more fundamental units are called derived units.FACTS WITH REASONSUnit of force is a derived unit. Why?From the definition of force, Force = Mass × Accelerationor, unit of force = unit of mass × unit of acceleration = kg × ms2 = kg m s –2Here, the unit of force (N) can be expressed in terms of kilogram (kg), metre (m) and second (s). So, it is a derived unit.Unit of power is a derived unit. Why?Power = work donetime = force × displacementtime = mass × acceleration × displacementtimeUnit of power = kg × m s–2 × ms = kg m2s3 = kg m2 s –3Thus, Watt, the SI unit of power is derived from three fundamental units, namely kilogram (kg), metre (m) and second (s). So, it is a derived unit.Some derived physical quantities with their unitsSN. Physical quantities Formulae SI units Symbols Fundamental units involved1. Area length × breadth square meter m2 m × m2. Volume length × breadth × height cubic meter m3 m × m × m3. Density mass / volume kilogram per cubic meter kg/ m3 kg/(m × m × m)4. Velocity displacement / time meter per second m/s m/s5. Acceleration change in velocity / time meter per square second m/s2 m/(s × s)MEMORY TIPSThe combination of many basic units makes a derived unit. Sometimes, the derived unit is given a special name. For example, the derived unit of displacement is m/s. It is made of basic units m and second. The derived unit of power is kgm2/s3. This derived unit is named Watt.

8 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 96. Force mass × acceleration newton kgm/s2 , N kg m/(s × s)7. Power work / time joule per second or watt J/s or W kg × m× m /(s × s × s)8. Frequency 1/time per second or Hz s-1 or Hz ¹/s9. Work or Energy force × displacement joule J kg × m × m/(s × s)10. Pressure force/area newton per square metre or pascal Nm-2or Pa kg/(m × s × s)11. Momentum mass × velocity kilogram metre per second kg m/s kg×(m/s)12 Resistance Voltage / current Ω kgm2s-3A-2kg × ms–2 × mA × A × sProject WorkObserve in your surrounding and find out the fundamental and derived units used to measure different physical quantities. Compare with your friend and discuss in the class.Differences between fundamental units and derived unitsS.N. Fundamental units S.N. Derived units1.The units which are independent from other units are called fundamental units.1.The units which are derived from the combination of two or more fundamental units are called derived units. 2. They are basic units. 2. They are derived from basic units.3.In SI units, there are seven fundamental units. They are m, kg, s, K, A, cd and mol. 3. In SI units, there are many derived units. Examples : m2, m3, m/s, N, W, J, etc.Unit-wise analysis of physical equationUnit-wise analysis of an equation is the study of the relationship between physical equations with the help of units of measurement. The principle of homogeneity states that an equation is unit-wise correct if the units of the various terms on either side of the equation are the same. It helps us to check the validity of the equation. The validity of an equation is checked by observing the units on the left-hand side and the units on the right-hand side of the equation. If the units on the right-hand side of the equation are equal to units on the left-hand side of the equation, the equation is valid. Otherwise, the equation is invalid. Only the physical quantities having the same composition of units can be added. The physical quantities having different components of units cannot be added. For example, if the length of the rectangular box is 30 cm and its breadth is 20 cm, then its perimeter will be length + breadth + length + breadth = 2(length + breadth) = 2 (30 cm + 20 cm) = 2 × 50 cm = 100 cm. Here we were able to add the length of four sides of the rectangle because all of them had the same units.

8 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 9However, if the area of the rectangle is 600 cm2 and the volume of the box is 600 cm3, we cannot add these two physical quantities because they have different units. The components of their units are different. The principle of homogeneity of equationsThe principle of homogeneity states that an equation is unit-wise correct if the units of the various terms on either side of the equation are same. This principle is helpful because it helps us convert the units from one form to another. To better understand the principle, let us consider the following examples:Solved Numerical 1.1Check the correctness of physical equation v = u + at2. In the equation, u is the initial velocity, v is the final velocity, a is the acceleration and t is the time in which change occurs.Solution:We know that L.H.S = v and R.H.S = u + at2The units for the L.H.S can be written as v = metre per second (ms-1) ………..(1)We know that R.H.S is u + at2Simply, we can write R.H.S as u + a × t2 (Since numerical coefficient does not matter)or, ms- 1 + ms-2 × s2 or, ms-1 + m……….…….……..(2)Keeping equation (1) and (2) together, we have,ms-1 ≠ ms-1+ mFrom equation (1) and (2), we do not have L.H.S = R.H.SHence, by the principle of homogeneity, the given equation is unit-wise incorrect and it is non-homogenous.Solved Numerical 1.2 Check the correctness of the physical equation v2 = u2 + 2as2.Solution:We know that L.H.S = v2 and R.H.S = u2 + 2as2The units for the L.H.S can be written as v2 = metre2 per second 2 (m2 s-2) ………..(1)We know that R.H.S is u2 + 2as2Simply, we can write R.H.S as u2 + a × s2 (Since numerical coefficient does not matter)or, m2s-2 + ms-2× m2 or, m2s-2 + m3s-2……….…….……..(2)Keeping equation (1) and (2) together, we have,m2s-2 ≠ m2s-2 + m3s-2

10 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 11From equation (1) and (2), we do not have L.H.S = R.H.SHence, by the principle of homogeneity, the given equation is unit-wise incorrect and non-homogenous.Applications of unit-wise analysisAnalysis of unit-wise equations is a crucial component of measurement, playing a vital role in practical physics applications. This approach serves several purposes:i. Verifying the credibility of a physical equation.ii. Establishing relationships between various physical quantities within an equation.iii. Facilitating the conversion of units between different systems.iv. Evaluating the validity of an equation.Limitations of unit-wise analysisUnit-wise analysis has certain limitations, including:i. Lack of information about equational constants.ii. Absence of details regarding the coefficients in the equation.iii. Inability to provide information about whether a physical quantity is a scalar or vector.HOT SKILL HIGHER ORDER THINKING SKILL1. What is the main thing to distinguish independent and dependent variable?The variable whose value can be changed by the scientists during their experiment is called independent variable. Similarly, the variable whose value depends upon the value of other variables is called dependent variable.2. Is equation P = I2R acceptable ?Yes, equation P= I2R is acceptable because the basic units involved in P is kgm2s-3 and I2R is also kgm2s-3 .3. Acceleration is called a derived physical quantity. Why?We know that, acceleration = Change in velocitytime takenHere, acceleration is expressed with the help of two fundamental quantities i.e., displacement, and time. Therefore, acceleration is a derived physical quantity.4. Differentiate between MKS system and the SI units.S.N. MKS system S.N. SI units1. MKS system is a metric system of measurement.1. SI units is a revised, redefined and extended version of the MKS system.2. It involves three fundamental quantities, i.e. length, mass and time. 2. It involves seven fundamental quantities.5. Distinguish between dependent and independent variables.S.N. Dependent variables S.N. Independent variables1. The variables whose value is dependent upon the independent variables are called dependent variables. 1. The variables whose value can be changed by us freely are called independent variables. 2. It is called left variable and y-variable. 2. It is called right variable and x-variable. 3. It is also called vertical variable. 3. It is also called horizontal variable.

10 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 116. Is it possible to add and subtract physical quantities having different basic units?No, we can not add and subtract physical quantities having different basic units. It means that only those physical quantities can be added or subtracted which have same units. For example addition or subtraction of 'u' and 'v' is possible because they have same basic units, i.e., ms-1. Similarly, s+at is not possible because 's' has basic unit 'm' and 'at' has basic unit ms-1.7. Show that joule is a derived unit.Joule is the SI unit of work.So, work = force × distance = mass × acceleration × distance = kg × m/s2 × mFrom this observation, we can tell that the SI unit of work is joule and it is a derived unit because it is dependent upon other fundamental units such as kg, meter and second. 8. Can unit-wise analysis tell about the equational constant? What are the other limitations of unit-wise analysis? No, a unit-wise analysis cannot tell about equational constant. Some other limitations of unit-wise analysis are: It cannot tell about equation’s coefficient. It cannot tell if the physical quantity is vector or scalar. 9. Variables are important.Variables are important because they can be observed and used to derive formulas for certain physical quantities. It can be used to understand the relation between various physical quantities. 10. Nilu wants to observe heat absorb by different colours. For this she brought twelve coloured jugs ( three black, three blue, three white and three red) of equal size. She fill water and put them in the sun light for two hours. After that, she brought a thermometer and measure temperature. Based on this experiment, answer the following questions. i. What are dependent variable, independent variable and controlled variables in this experiment?In this experiment colour is an independent variable, temperature is dependent variable, size of jugs, amount of water and time duration are controlled variables.ii. Why did she brought equal size of jugs and kept them in the sunlight for equal time?In this experiment, she wants to study the relation between colours and heat absorbed (change in temperature). So, size of jugs, amount of water and time duration are kept constant as they are controlled variables.iii. Why did she bring three jugs of each colour?For correct measurement, we should not depend upon only one reading. The mean value of more than one reading gives the correct measurement. For the same purpose Nilu brought three jugs of each colour.4 STEPS EXERCISE EXERCISESTEP11. Select the best answer from the given alternatives.a. What is the name given for the factors, traits or conditions that are considered during an experiment? i. variety ii. variables iii. variation iv. variabilityb. What variables are called vertical variables? i. dependent variable ii. independent variable iii. mixed variable iv. controlled variable

12 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 13c. Which physical quantity is the ratio of mass to volume? i. length ii. momentum iii. density iv. temperatured. Which one of the following is a dependent variable?Changes during an experiment Does not change during the experiment Changed by us A BNot changed by us C D i. A ii. C iii. B iv. D e. Which of the following order is the correct order of variables?i. change in dependent variable → change in independent variable → change in controlled variable ii. change in controlled variable → change in dependent variable → change in independent variable iii. many variables are controlled → change in independent variable → change in dependent variable iv. change in controlled variable → change in independent variable → change in dependent variable f. What describes the independent variable? i. right variable, x-variable, horizontal variable ii. left variable, y-variable, vertical variable iii. controlled, changed, x-variable iv. not dependent upon scientists, vertical variables g. In the given equation s = v x t, where ‘s’ means displacement, ‘v’ means velocity and ‘t’ means time, which of the following options proves its validity? i. m = m/s2 ii. m = ms × s iii. m = kg × s iv. m = ms-1 × sh. Arya says, ‘There are many variables in an experiment’. Elle says, ‘Yes! There are multiple controlled variables in an experiment. Then Eleonor replies that there is only one dependent variable and only one independent variable in an experiment. Who is correct or incorrect? i. Arya is correct but Elle and Eleonor are incorrect. ii. Elle is correct but Arya and Eleonor are incorrect. iii. Arya, Elle and Eleonor are correct. iv. Eleonor is correct but Arya and Elle are incorrect. i. Which of the following is a set of fundamental units? i. m, N, Kg ii. Cd, mol, second iii. kg, m, Joules iv. m/s, kg, s j. What kind of variable is B? A gets changed Bitseflshould be changed by usvariable

12 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 13i. dependent variable ii. independent variable iii. mixed variable iv. controlled variable a. ii b. i c. iii d. ii e. iii f. i g. iv h. iii i. ii j. ii Ans of MCQSTEP22. Very short questions a. Define controlled variable. b. How many fundamental quantities are there in the SI unit?c. If we want to check the solubility of salt at different temperatures, what should be the controlled variable?d. SI unit of frequency is Hertz which is 1s. Why is it a derived unit even though it is made of only one basic unit? e. Study the given table and identify the type of variable being discussed.Changes Number Changed by researcher Variable Seen 1 Nof. In the equation v = u + at, we cannot add u + at. Why?g. What is the application of analysis of unit-wise equations?h. What are the units with independent existence called?i. What is the SI unit of luminous intensity? STEP33. Short questions a. The unit of length, the meter is called the fundamental unit. Why?b. What are the differences between the fundamental unit and the derived unit?c. Observe the graph given below and identify the dependent and independent variables. d. The SI unit of resistance is ohm (Ω). Express this SI unit into its fundamental units. e. Umanath Neupane put two identical flower plants in a flower vase and watered them equally. He put one in a bright place and another in a dark room. The one in the darkroom became yellow and the one in the bright place became green. What kind of variable is the amount of water in this experiment? Why?

14 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 15f. Write the characteristics of controlled variables. g. Perform analysis of unit-wise equation. i) v = u + at (v is final velocity, u is initial velocity, a is acceleration and t is time)ii) h = ut+ 12 gt2 (h is height, u is initial velocity, t is time, g is acceleration due to gravity)iii) P = IV (P is power, I is current, V is voltage)iv) V = IR (V is voltage, I is current, R is resistance)h. Is equation F=ma acceptable? Prove it. Here ‘F’ is force, ‘m’ is the mass of the object and ‘a’ is acceleration. Is the unit of force derived or a fundamental unit based on the above observation? STEP44. Long questions a. Alish wants to observe the growth of plants in different fertilizers like urea, compost fertilizer and wooden ash. He brought three vases and kept an equal amount of urea, compost fertilizer and wooden ash in each. He sown seeds of the same plant and kept them in the open place. After the germination of seeds, he measured their height each day and maintained a record. Based on this experiment answer the following questions. What are the independent variable, dependent variable and controlled variables in this experiment? Why did he bring vases of equal size and keep an equal amount of fertilizers? b. Lokeshwor has a cow farm. He increased the food to one group of cows and kept it constant for others. The group that ate more food gave more milk than the others. Enlist dependent and independent variables in this experiment along with their reason. c. Munal says the formula of power P = Force × distancetime and Rohan says Power = forcevelocity. Who is correct? Check using unit-analysis. d. Design an activity where we can identify independent variables, dependent variables and controlled variables. e. Emon learnt that the area of the rectangle depends on the length and breadth of the rectangle. He wanted to know the relation between the area of the rectangle and its length. Hence, he decided to do an activity where he kept the breadth constant. He continuously altered the length multiple times and recorded the data. After analysis, he realised that the value of the area increased when the length was increased and the value of the area decreased when the length was decreased. He concluded that the area of the rectangle is directly proportional to the magnitude of the length. From this activity, answer the given questions.i. Why the magnitude of the length is called the right variable?ii. In the above activity, which physical quantity is called a controlled variable and why?iii. What are the advantages of keeping the breadth of the rectangle constant in this experiment?

14 Scientific Study Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 15Key terms and terminologies of the unit1. Classification of organisms: Classification is the act of grouping of organisms on the basis of their similarities and dissimilarities.2. Taxonomy: The branch of science that deals with the identification, classification and nomenclature of organisms is called taxonomy.3. Genus: Genus represents the group of those organisms that have similar physiology, anatomy and feeding habit.4. Species: Species represents the organisms that are completely similar to each other and can interbreed to produce a fertile offspring.5. Unicellular organisms: The organisms which are made of only one cell are called unicellular organisms.6. Multicellular organisms: The organisms which are made of many cells are called multicellular organisms. 7. Prokaryotes: The organisms which do not have nuclei and membrane-bound cell organelles in their cells are known as prokaryotes. 8. Eukaryotes: The organisms which have a nucleus and membrane-bound cell organelles in their cells are known as eukaryotes. 9. Autotrophs: The organisms which can prepare food by themselves are called autotrophs. 10. Heterotrophs: The organisms which cannot prepare food by themselves are called heterotrophs. Sequence of Curriculum Issued by CDC Classification of living beings: based on five kingdom system Classification of plant kingdom: features and examples upto division Sub-division Angiosperm: features and examples of upto class Classification of animals: features and examples upto phylum Sub-phylum Vertebrata: features and examples upto class Relation of evolution with the classification of organismsUNITClassification of Living Things2Estimated teaching period Theory Practical6 3Sushila Maharjan, born in Nepal, has made remarkable contributions to the fields of microbiology and genetic engineering, particularly in the realm of medical applications. Her research delves into harnessing the potential of soil microbes for medical use and pioneering the development of new antibiotics. Co-founding the Nepal Research Institute for Bioscience and Biotechnology, Maharjan's work has earned her global acclaim, including the esteemed Elsevier Foundation Award in 2016. Sushila MaharjanAbout the Nepalese Scientist

16 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 1711. Saprophytes: The organisms that absorb nutrients directly from decaying organic matter are called saprophytes.12. Parasites: The heterotrophs that live in the body of host organisms for nutrients and harm them are called parasites. 13. Algae: The plants with thallus bodies and chlorophyll are called algae. 14. Bryophytes: The plants that have thallus or non-thallus bodies without vascular tissue are called bryophytes. 15. Tracheophyta: The division of non-thallus plants which contains vascular tissue is called tracheophyta. 16. Closed circulatory system: The blood circulatory system in which the blood flows inside the blood vessels when pumped by the heart is called a closed circulatory system. 17. Open circulatory system: The blood circulatory system in which blood flows directly into the tissues without blood vessels is called the open circulatory system. 18. Diploblastic organism: An organism which has two germ layers in its embryonic stage is called a diploblastic organism. 19. Triploblastic animals: An organism which has three germ layers in its embryonic stage is called a triploblastic organism. 20. Hermaphrodites: Animals which have both a male reproductive system and a female reproductive system are called hermaphrodites or bisexual animals. 21. Invertebrates: The animals which do not have a vertebral column in their body are called invertebrates. 22. Chordates: The animals which bear notochord and pharyngeal gills in some stages of their life are called chordates. 23. Vertebrates: The animals that have notochord in their embryonic stage which modifies into a backbone or vertebral column are called vertebrates. 24. Cold-blooded animals: The animals whose body temperature changes according to the surrounding temperature are called cold-blooded animals. 25. Warm-blooded animals: The animals whose body temperature does not change according to the surrounding temperature are called warm-blooded animals. 26. Oviparous animals: The animals which reproduce by laying eggs are called oviparous animals. 27. Viviparous animals: The animals which reproduce by giving birth directly are called viviparous animals.

16 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 17IntroductionObserve the following figures and discuss the given questions.(a)(e)(b)(f)(c)(g)(d)(h)i. Can we keep these animals together in a same phylum? ii. What are the similarities and differences between pigeon and frog?iii. What are the differences between mushroom and pine tree?Let's observe the estimated total population of different groups of plants and animals found on the earth. We can see that, there are about 5,500 mammals, 10,000 reptiles, 40,000 fishes, 15,000 amphibians, 10,000 birds and 6,755,830 invertebrates in the world. If we examine the names and characteristics of all these species, the variation is so huge that it becomes impossible to study each of them. There is also difficulty of language for the study of these organisms around the world. This problem is solved by grouping the plants and animals on the basis of their similarities and differences into certain types. This is known as classification of plants and animals.Classification of organisms is the act of grouping organisms on the basis of their similarities and dissimilarities. It was first done by Swedish biologist Carolus von Linneaus in the 1750s. Carolus introduced a system known as the Binomial system of Nomenclature in which the plants and animals were given a unique name called the scientific name. The scientific name consists of two Latin words: the first word is called the genus or the generic name and the second one is called thespecies or specific name or epithet. Today, all known organisms in the world have a universal scientific name that every biologist understands irrespective of his language and country. The system Carolus started is well developed into a branch of biology known as the Taxonomy. Carolus von Linnaeus is known as the father of taxonomy.MEMORY TIPSThere are about 8.7 million species of living things in the earth.MEMORY TIPSTaxonomy is the branch of biology which deals with identification, classification and nomenclature of organisms.

18 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 19FACTS WITH REASONSCarolus von Linnaeus is known as the father of taxonomy, why?Carolus von Linnaeus started the systematization in the classification process through Binomial system of nomenclature for the first time. So, Carolus von Linnaeus is known as the father of taxonomy.Classification HierarchyCommonly, there are two kinds of organisms: plants and animals. These plants and animals have further types and sub-types. Look at the simple classification of a bird hen:Hen falls under the 5th common level of animals’ type. The types in which hen is classified forms a hierarchy. In this example, there are five groups forming a hierarchy. Each group level of hierarchy is known as a taxon. A taxon is a generally accepted category under which the organisms having similar characteristics are grouped. There are various taxa (pl. of taxon) which form a hierarchy of classification. The classification hierarchy is shown below:Kingdom Phylum Sub-phylum Class TypeAnimalia Chordata Vertebrata Aves HenThe Five Kingdom SystemThe two kingdom system (Plantae and Animalia) could not distinguish between prokaryotes/eukaryotes, autotrophs/heterotrophs and unicellular/multicellular. There were many organisms that did not fit in the two kingdom system satisfactorily. Therefore, American Biologist Robert H. Whittaker proposed the five kingdom system, adding three more kingdoms: Monera, Protista and Fungi, in addition to the earlier two kingdoms: plantae and Animalia. The five kingdom system is explained in brief below:5 Kingdom SystemMoneraUnicellular prokaryotesPlantaeMulticellular autotrophic eukaryotesAnimaliaMulticellular heterotrophic eukaryoticsFungiNon-green multicellular eukaryotesProtistaUnicellular eukaryotes1. MoneraThis kingdom includes all types of bacteria (e.g. cyanobacteria or blue-green algae, coccus, bacillus, etc.). They are single-celled microscopic prokaryotes having no nuclear membranes. They are both autotrophic and heterotrophic. Bacteria Coccus Blue-green algaeMEMORY TIPSKingdom monera consists of onecelled organisms, both autotrophs and heterotrophs that are extremely simple in structure.

18 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 192. ProtistaThis kingdom includes single-celled microscopic eukaryotes. i.e. they contain a well-defined nucleuswith membrane bound cellular structures. They have a nuclear membrane and are both autotrophic and heterotrophic. For example, amoeba, paramecium, euglena, dinoflagellates, etc. Their locomotory organs are primitive. 3. FungiFungi is the kingdom of non-green eukaryotes. They are multicellular. They cannot prepare food by themselves and are heterotrophic. Hence, they have to depend upon dead and decayed matter for food. Most of the fungi are filamentous and thread-like in structure.Mushroom Yeast Mucor4. PlantaeThese are well-developed multicellular organisms. They have a eukaryotic cell and can prepare food by themselves (autotrophic). Plants lying in this kingdom are both higher and lower type. The herbs, shrubs and trees are parts of this kingdom. Characteristics of plant kingdom: i. The cell contains a cell wall which is made up of cellulose. ii. Most of the plants store carbohydrates such as starch. iii. Most of the plants prepare their own food by photosynthesis.iv. Multicellular, eukaryotic, containing chloroplast 5. AnimaliaThe organisms lying in this kingdom are multicellular, eukaryotic and heterotrophic. They have different forms of habitats. Most of them have well developed tissue, organ and body systems. They swallow their food as a whole and have a digesting column in the body (holozoic in nature). Their cells do not have a cell wall.Amoeba Paramecium EuglenaMEMORY TIPSFungi are useful in our daily life too. The fungus called yeast is used to prepare beer and bread. Similarly, antibiotics are extracted from a fungus called penicillium. Mushroom is a fungus which has several medicinal values. But, some fungus are parasitic too e.g. puccinia, yarshagumba etc.Mango Moss Fern

20 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 21Dolphin Frog StarfishFACTS WITH REASONSThe five-kingdom classification system is considered the most widely accepted system of classification.The five-kingdom classification system is considered the most widely accepted system of classification because it is widely accepted due to its effective grouping of diverse organisms into five distinct categories. This classification is based on the complexity of cell structure (Prokaryote or Eukaryote), the complexity of the organism's body (Unicellular or Multicellular and Complex), and the mode of nutrition (Photosynthesis, Absorption, or Ingestion). Kingdom Plantae [Latin: 'planta'- shoot]ACTIVITY 1Observe the given plants and answer the following questions.(a) (b) (c) (d)i. Name the given plants.ii. Write down the major characteristics of the given plants.The kingdom plantae includes the multicellular, autotrophic eukaryotes. This kingdom contains plants living in all types of habitats. They may vary in shape, size and body features. On the basis of their habitats there are two types of plants: terrestrial and aquatic. All herbs, shrubs, trees, creepers, etc. fall under this category. The plant kingdom is divided into three divisions. They are algae, bryophyta and tracheophyta.i) Division algae [Latin: 'alga'- sea weed]Algae are the wide range of small, thalloid and green plants that are autotrophic in nature. They are mostly seen as green, red, brown, yellow-green, golden and purple patches in the sea, pond, and rivers. They may cover up the entire pond or seacoast that gives a colourful effect to the water. Their bodies are thalloid i.e. cannot be differentiated into roots, stem and leaves. Hence, they are called thallophytes. Their main characteristics are given below:a) Body type: They are thallus. b) Mode of nutrition: They are autotrophic and can prepare food by themselves. Green algae have chlorophyll while other colourful algae may have other colourful pigments too.

20 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 21c) Habitat: Most algae live in the water sources like the pond, lake, sea, etc. by attaching to their bed. Some of them live in moist places too.d) Food storage: The algae store their food in the form of a carbohydrate called starch (starch is a common source of foods like rice, wheat, potato etc.).e) Cell wall: They bear cell wall like all other plants. Their cell wall contains cellulose.f) Reproduction: They reproduce both through the vegetative and sexual method. g) Vascular tissues: Absenth) Alternation of generation: AbsentExamples: Green algae (e.g. spirogyra, volvox, ulothrix, chlamydomonas, etc.), diatoms (golden brown algae), dinoflagellates (fire algae), rhodophytes (red algae), Laminaria (brown algae), fucus etc.FACTS WITH REASONSFucus is an algae and Marchantia is a Bryophyta even though they look the same. Even though fucus and Marchantia look the same they belong to different divisions because fucus is thallus so it belongs to algae and Marchantia has rhizomes and leaves. So, it belongs to Bryophyta. SpirogyraAnabaena NostocUlothrixBatraVolvoxLamnariaii) Division Bryophyta [Greek: bryon – moss and phyton - plant]Bryophytes are the flowerless plants (cryptogams) that grow in moist, shady, damp and watery places. They are commonly divided into three groups of plants: liverworts, mosses and hornworts. Mosses form the largest family of bryophytes. Some of their common characteristics are:a) Body type: The body of bryophytes is multicellular. They are both thallus and non-thallus. They do not grow tall because they do not have vascular tissue.b) Mode of nutrition: Bryophytes are green plants. They contain chlorophyll and the mode of nutrition is autotrophic.MEMORY TIPSMosses do not have vascular tissue but still they have rhizoids, stems and leaves.

22 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 23c) Habitat: Most of the bryophytes grow in moist and shady areas because they need water for fertilization.FACTS WITH REASONSRiccia is an amphibian plant.Riccia is an amphibian plant because it needs water for fertilization. So, they live in damp soil near water sources. d) Food storage: They store food in the form of starch.e) Cell wall: The cell wall of bryophytes is made up of cellulose.f) Reproduction: They reproduce by both vegetative and sexual method.g) Vascular tissues: Absenth) Alternation of generation:Life cycle of bryophytes is divided into two stages: sporophytic and gametophytic. The sporophytic generation is followed by the gametophytic and vice versa. This is called the alternation of generation.Most bryophytes are unisexual (dioecious). Some of them can be bisexual too. Usually, the leaf of the bryophyte has reproductive parts. It could be the male reproductive part or the female reproductive part. The male reproductive part is called antheridium. There are many antheridia in the leaf. The antheridia produces a male gamete. The female reproductive part is called the archegonium. There could be many archegonia in the leaf. The archegonia produces eggs. This part of the bryophyte is called gametophyte because male and female gametes are formed here. The gametophytic generation of the bryophyte is longer than the sporophyte. When the water is available on the leaf, the male gamete will swim towards the female gamete. They will fertilize to form a zygote.Sporophyte:The zygote formed inside the archegonium will germinate into a sporophyte. Sporophytes are underdeveloped and short-lived. It remains attached to the gametophyte. Later, the spore mother cell of the sporophyte will do meiosis cell division to produce four haploid spores.This stage is called sporophytic generation because of the formation of spores. The spores will spread far away from the main plant and germinate into new gametophytes. Hence, the alternation of generation continues the lifecycle of bryophyta.Examples: Moss (e.g. sphagnum, fire moss, funaria etc.), liverworts (e.g. marchantia, riccia, etc.), etc.Marchantia Riccia Irish moss

22 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 23iii) Division Tracheophyta [Greek: 'trakheia' - windpipe and ‘ophyta’ - to produce]Tracheophyta is the division which includes vascular plants. Vascular plants are those which have vascular tissues called xylem and phloem. These tissues make transport system in plants. They conduct food and minerals throughout the plant body. Xylem tissues conduct raw materials from the roots to the leaves while the phloem tissues conduct food prepared in the leaves to all parts of the plant body. The tracheophyta includes cryptogams which are non flowering plants and the phanerogams which are flowering plants. They also contains herbs, shrubs, trees and coniferous plants.The division Tracheophyta, also known as the vascular plants, is divided into three subdivisions. They are Pteridophyta the one with feathery leaves and no flowers, gymnosperms the ones with naked seeds in the cones and the angiosperms ones with the closed seeds in the fruits.FACTS WITH REASONSTracheophytes are called vascular plants.The tracheophytes are called vascular plants because they have xylem and phloem, which are vascular bundles that can help in the transportation of water, minerals and food throughout the plant. Sub-division Pteridophyta [Greek: ‘pteris’ - fern like and ‘phyton’ - plant]Pteridophytes are the most developed non-flowering plants. They do not bear flowers, fruit and seeds. As they are tracheophytes, they bear vascular tissues: xylem and phloem. Some of the characteristics of pteridophytes are given below:a) Habitat: Most pteridophytes grow in open, moist, and shady places. Some species grow on rocky hillside, banks and cliffs, ponds and some under sunlight. b) Body size and structure: Most pteridophytes are small in structure bearing feather-like leaves called fronds, underground stem called rhizome and developed roots called rhizoids. Some tropical tree ferns can be as tall as 30 m.c) Flower, fruits and seeds: They do not bear flowers, so they do not produce fruits and seeds. d) Mode of nutrition: All pteridophytes are green and bear chlorophyll to produce their own food. Therefore, the mode of nutrition is autotrophic.e) Differentiation: The body of pteridophytes is non-thalloid i.e. divided into roots, stem and leaves. The roots of Pteridophyta are called rhizoids. They are developed. The fleshy underground stem of the Pteridophyta is called a rhizome. They are less developed. The leaf is feathery. The new leaf is called a frond.f) Vascular tissues: As pteridophytes are tracheophytes, they bear vascular tissues for food and mineral conduction.g) Reproduction: Pteridophytes do not bear male and female parts in their mature plant body but grow later on in their life cycle. They have both asexual and sexual reproduction systems present in their life cycle. They reproduce asexually by spores. Spores are the numerous tiny structures present in the ventral part of sporophyll inside the sorus (spore MEMORY TIPSFern is a non-flowering plant. Cycas bears flower-like cones but no fruit. Banana bears flowers and fruit. They are different. However, all these plants are kept in the same division Tracheophyta because all of them have vascular tissue.

24 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 25sac). Likewise, the sexual reproduction occurs afterwards by the union of male and female sex gametes.h) Alternation of generation: The life cycle of pteridophytes is completed in two stages: sporophytic generation (stage of spores) followed by the gametophytic generation (stage of gametes). So, alternation of generation exists.The plant body of the fern is sporophyte and is seen for a longer duration (dominant). It has sporophyll. Sporophyll is a leaf which has sorus. Sori are dark and black spots on the back side of the sporophyll. The leaf without sorus is called tropophyll. Sorus has sporangium. The sporangium is a structure where spores grow. The sporangia produce tons of spores. On maturity, spores fall into suitable ground and germinate into prothallus. Gametophytic generation: Gametophyte is a heart-shaped green structure that has roots. It is also called prothallus. It is short-lived in the fern plant. It contains male and female parts. It is bisexual. The male part of the prothallus is called antheridium. Antheridia produce antherozoids. The female part of prothallus is called archegonium. Archegonia produces ovum. The prothallus is called gametophyte because it produces gametes. When the antherozoids swim towards the ovum, meet the ovum and fuse with the ovum, a zygote is formed. The zygote will grow into a new plant. Gametophyte is also called amphibian because it needs water for fertilization. Since they need water for fertilization, fern grows in moist places. The gametophytic generation and sporophytic generation come alternately in the life cycle of the fern plant. Hence the life cycle of the fern continues.Examples: Fern, Lycopodium, Equisetum or Horsetail, Marsilea, fiddlehead fern, ground gooseberry, selaginaella, Pteris etc.Fern Lycopodium Equisetum Selaginella MarsileaFACTS WITH REASONSClub moss is more developed than moss.Club moss is more developed than moss because club moss has vascular bundles of xylem and phloem but moss does not. Sub-division: Gymospersms [Greek: 'gymno'-naked and 'sperma'- seed]Gymnosperms are the plants that do not bear fruits but they have naked seeds. Their seeds are not enclosed inside the fruits. That is why they are called naked seeded plants. Their characteristics are given below:MEMORY TIPSGymnosperms are the first seedbearing plants.

24 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 25a) Habitat: Gymnosperms are terrestrial plants which grow on dry places that receive less rainfall.b) Body size and structure: They are mostly bigger trees with woody parts. Their leaves are needle shaped. They grow in dry place. So, they have very long roots that go very far to search for water.c) Flower, fruits and seeds: They do not bear flowers and fruit because they do not have ovary but they contain seeds. The seeds are naked and not enclosed inside fruits (like in mango) or seed covering (like in paddy). Instead of flowers, they bear woody scales called the cones. The male and female cones are separate. They are unisexual. The cones helps in reproduction.FACTS WITH REASONSGymnosperms are called coniferous plants.Gymnosperms are called coniferous plants because these plants look like inverted cones in a pole. d) Mode of nutrition: All gymnosperms are autotrophic in nature as they are green plants.e) Differentiation: Their bodies are well differentiated into roots, stems and leaves.f) Vascular tissues: All gymnosperms bear vascular bundles. They are not well developed as in angiosperms.g) Reproduction: Pollination in gymnosperms is caused only by the wind and insects. After pollination, the pollen cells from the male cone fuses with the female cell present in the female cone. Thus, the fertilization occurs.Examples: pine, fir, spruce, deodar, gingko, cycas, pinus, juniper, himalayan yew, Himalayan ceder etc.Cycas Pine CedarSub-division: Angiosperms [Greek: 'angion' - coat and 'sperma' - seed]Angiosperms belong to about 300,000 species of the most advanced flowering plants of the Plantae kingdom. They are found both on land and in water and are the most advanced plants. Examples, soyabean, orange, maize, bamboo, banana, banyan, cactus, paddy, wheat, water hyacinth, Lemna, pistia, etc. Some of the reasons why they are considered the most advanced plants are as follows:i. They have well developed vascular tissues: xylem and phloem.ii. They bear well developed flower, fruit and seed.iii. They are all multicellular, non-thalloid and green plants.MEMORY TIPSSub-divisions of plants can be predicted from their leaves too. Pteridophyta have feather-like leaves, gymnosperm have needlelike leaves and angiosperm flat leaves with a midrib and veins. MEMORY TIPSThe orange tree is more advanced than the Cycas because the orange tree has true flowers and fruits but Cycas do not.MEMORY TIPSCycas belongs to gymnosperm whereas coconut belongs to angiosperm. So, coconut is more developed plant than cycas as it has closed seed.

26 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 27iv. Seeds are enclosed inside the fruits and ovules are enclosed inside the ovary of the flowers.v. Flowers are both unisexual and bisexual.vi. Their size ranges from small herbs to large trees.On the basis of the number of leafy parts of a seed (cotyledon), the angiosperms are divided into two major classes:a. Class: Monocotyledon / monocotyledonous / monocot plantsb. Class: Dicotyledon / dicotyledonous / dicot plantsMonocotyledon: [mono - one]The monocots are those plants which have a single cotyledon or leafy part in their seeds. They are found in various habitats and grow in wide ranges of climates. Their stems and branches are soft and do not contain woody parts. Some of them are aquatic and some of them are terrestrial. They have enclosed seeds with one cotyledon. They constitute about 60,000 species. Examples are paddy, bamboo, banana, barley, turmeric, wheat, sugarcane etc.Dicotyledon: [Di - two]The dicotyledons are the plants which bear two cotyledons in their seeds. They mostly are terrestrial plants and have woody stems. There are about 200,000 species of dicots on earth. Examples are, soyabean, gram, mustard, orange, apple, pea, mango, beans, pumpkin etc.A short comparison between monocots and dicots along with their characteristics on the basis of various features are given below:Characteristics of monocotyledon and dicotyledonFeature Monocot DicotSeed The seed bears one cotyledon.The seed bears two cotyledons.Leaf venationLeaves have parallel venation. Every other veins are parallel to midrib. Leaves do not have petiole. Leaves are attached to the stem. Leaves are long and narrow.They have broad and flat leaves. They have reticulate venation in the leaves. It is also called network venation because venules looks like a net. Many minute venules rise from main vein called midrib. The leaves have petiole. They can have simple leaves or compound leaves. Monocot seedMEMORY TIPSFern, cycas, banana, etc. have vascular tissue so, they are kept in division tracheophyta.Dicot seed

26 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 27Root Root system is fibrous. All roots arise from same place and almost equal in length. They do not have main root.Root system is tap root. They have a main root. Secondary roots grow from main roots. They have tertiary roots and root hairs too.Flower Flower bears petals in multiples of three (trimerous)Flower bears petals in multiples of five or four (tetramerous or pentamerous)Vascular tissuesThe stems have irregularly scattered vascular bundles The stems have vascular bundles arranged in a ring. Stem They have hollow spongy stem. Nodes are clearly visible. Nodes are at equal distance. Branch and leaf grow from nodes.Nodes are at unequal distances from each other.Pollen grainThe pollen grains have single opening. Examples: cereals (rice, wheat, etc.), flowers like daffodil, orchid etc., grasses, banana, bamboo, water plants (pistia, lemna, water hyacinth etc.), sugarcane, onion, coconut, etc.The pollen grains have three openings. Examples: tomato, apple, mango, pumpkin, mustard, papaya, gram, rose, soya bean, pea, etc.MEMORY TIPSMonocot flower is identified from its trimerous structure where as dicot flower is identified from its tetramerous or pentamerous structure.Project WorkObserve in your surrounding and find out the different plants of angiosperm. Compare with the plants that are collected by your friend.FACTS WITH REASONSThe seeds of angiosperms are enclosed inside fruits or seed covering, why?Angiosperms bear flowers with ovule inside an ovary. The ovary changes into fruit and the ovule changes into seed. So, the seeds of angiosperms are enclosed inside fruits or seed covering.

28 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 29Kingdom Animalia [from Latin – animalis meaning ‘having breath and soul’]ACTIVITY 2Observe the given figures and discuss the following questions.(a) (b) (c) (d) (e) (f) (g) (h)i. Name the kingdom and phylum of these animals.ii. Enlist the major characteristics of these animalsAnimals are the multicellular, non-green eukaryotes having no cell wall in their cells. They are mostly found in marine water (e.g. seas, oceans), fresh water (e.g. lake, pond, river), deserts, grasslands, jungles etc. The animals without vertebral columns are called invertebrates and the animals with vertebral columns are called vertebrates. The invertebrates are classified into 8 phyla and the vertebrates are placed in only one phylum. The animal kingdom is simply divided into two parts. They are non-chordates and chordates. A chart below illustrates the classification of animals in an understandable manner. Phylum ChordataSub-phylum: UrochordataPhylum: Porifera e.g. syconPhylum: Coelenterata e.g. hydraPhylum: Platyhelminthes e.g. tapewormPhylum: Aschelminthes e.g. round wormPhylum: Annelida e.g. earthwormPhylum: ArthropodaPhylum: MolluscaPhylum: Echinodermata e.g. starfishSub-phylum: CephalochordataClass: Pisces e.g. rohu Class: Crustacea e.g. prawnClass: Amphibia e.g. frog Class: Insecta e.g. butterflyClass: Reptilia e.g. snake Class: Myriopoda e.g. millipedeClass: Aves e.g. parrot Class: Arachnida e.g. spiderClass: Mammalia e.g. humanSub-phylum: VertebrataAnimal KingdomGroup Non-chordata(notochord absent)Group Chordata(notochord present)Sub-phylum: Hemichordata

28 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 29Non-chordatesThese are the animals which do not have notochord in the embryo during their development.Since they do not have notochord, they do not bear a backbone. The non-chordates include the phylum of invertebrates: Porifera, Coelenterata, Platyhelminthes, Nemathelminthes, Annelida, Arthropoda, Mollusca and Echinodermata. They occupy about 97% of all animal species on earth.Classification of non-chordatesThe non-chordates are divided into eight phyla (singular-phylum) altogether which are explained below:1. Porifera [Greek: 'porus' – pore, 'ferre'– to bear]The poriferons are the most primitive multicellular animals which have pores all over their bodies. They live in both fresh water and marine water but not on land. They are commonly known as the sponges. The general characteristics of poriferons according to their body features are listed below:a) Body structure: These animals are rope, ball, vase or tube shaped. b) Special feature: The water canal system is found in porifera for nutrition and excretion. They have numerous small pores in their bodies due to which they are called poriferons. The numerous pores present on their bodies are called ostia (sing. ostium). Water along with food and oxygen enters into their body through ostia. Oxygen and food get absorbed by the inner wall of the body. A large opening is present in their body called the osculum (pl. oscula). It helps to excrete out wastes and water. c) Locomotion: They remain attached to the substratum and have no complex forms of movement except for few species which move inside water slowly. d) Body organization: Sponges are first multicellular organisms that lack true tissues, organs and systems. e) Symmetry: They are both asymmetrical and radially symmetrical. Radially symmetrical means their body is divisible into equal halves from any longitudinal planes.f) Germ layers: They are diploblastic animals with two germ layers in embryonic stage.g) Segmentation: They are asegmented.h) Reproduction: They reproduce asexually by budding and regeneration and sexually with the help of gametes.i) System:i) Respiratory system: Respiratory system is absent. They breathe by general body surface.ii) Excretory system: Absent. Excretion takes place through oscula.Examples: spongilla, sycon, cliona, euspongia, hylonema, leucosolenia, etc.Sycon Spongilla EuspongiaMEMORY TIPSAdult porifera are attached to the substratum.

30 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 31FACTS WITH REASONSPoriferons are called the simplest multicellular organisms, why?Poriferons are called simplest multicellular organisms because they are just a group of cells and do not have true tissues, organs and systems.2. Coelenterata [Greek: 'koilos' – hollow, 'enteron' – gut]a) Body structure: They have a hollow branched body. b) Special feature: Coelenterates have a hollow gut inside their bodies. Hence, the name coelenterate is derived from it. The hollow gut in their body is known as true coelom. It is also called coelenteron. It is also called gastrovascular cavity. It helps in digestion and transportation.c) Locomotion: The locomotion takes place with the help of tentacles which are also the organs of defence. d) Body organization: Coelenterates are multicellular organisms with simple tissues. They are first tissue graded organisms.e) Symmetry: They are radially symmetrical.f) Germ layers: They are diploblastic animals with two germ layers in embryonic stage.g) Segmentation: Asegmented (without segmentation)h) Digestive tract: They have an incomplete digestive tract. They possess a large opening at top called hypostome or mouth but does not have anus.i) Systems:i) Respiratory system: Respiratory system is absent. They respire through general body surface. ii) Reproductive system: They reproduce asexually by budding and regeneration. They reproduce sexually with the help of gametes.iii) Excretory system: Excretion takes place through body surface.iv) Nervous system: A network of nerve cells is present.j. Habitat: They are mostly aquatic found in lakes, ponds and sea.Examples: hydra, jellyfish, sea anemone, coral, rhizostoma etc.Hydra Jelly fish CoralFACTS WITH REASONSThe tentacle is useful for coelenterata. The tentacle is useful for coelenterata because it helps in locomotion and nutrition. Tentacles help them to obtain food. The tentacles have stinging cells called nematocysts. Nematocysts sting and paralyze or kill smaller organisms. The hydra feeds on those prey.

30 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 313. Platyhelminthes [Greek: 'platys' – flat, 'helminth' – worm]The phylum Platyhelminthes / flatworms are a group of 80% parasitic and 20% free living animals. They have the following characteristics:a) Body structure: The body is flat and long with ribbon, tape or leaf-like structure. b) Special feature: They have a dorsoventrally flat body. So, they are also known as flatworms.c) Locomotion: The locomotion takes place with the help of suckers, hooks or both. These organs are the organs for parasitism. d) Body organization: Coelenterates are multicellular organisms with simple organs. The organs are not well-developed. e) Symmetry: They are bilaterally symmetrical.f) Germ layers: They are the first triploblastic animals with three germ layers in embryonic stage.g) Segmentation: They do not have segmentation. h) Sexual orientation: They are bisexual animals (monoecious, hermaphrodite). Male and female reproductive systems are in the same body.i) Digestive tract: They have an incomplete digestive tract. They have a mouth but no anus.j) Systems:i) Reproductive system: They can only regenerate their injured body parts. Mostly sexual reproduction takes place with the help of gametes. They have internal fertilization. Planaria can reproduce by fragmentation and regeneration.ii) Excretory system: Excretion takes place through protonephridia or flame cells.iii) Nervous system: A bundle of nerves and a nerve cord are present.iv) Circulatory system: They do not have circulatory system.v) Respiratory system: They do not have respiratory system. They breathe by general body surface.Examples: liver fluke, tapeworm, planaria, turbellaria, diplozoon, otoplana, blood fluke. Tapeworm Liverfluke PlanariaFACTS WITH REASONSPlatyhelminthes has hookers and suckers.Platyhelminthes have hookers and suckers because hookers help them to attach to the alimentary canal and suckers help them to absorb nutrition. 4. Aschelminthes [Greek: 'ascus' – bladder, 'helminth' – worm]The animals belonging to this phylum range from 1 mm to 4 ft in length. They are also called nemathelminthes / nematoda / round worms / bladder worms / unsegmented worms. Some

32 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 33of their characteristics are as follows:a) Body structure: The body is round, slender, tapering and elongated.b) Special feature: They are unsegmented worms with both parasitic and non-parasitic nature.c) Locomotion: The locomotion takes place with the help of thick and tough cuticle.d) Body organization: Nematods have organs developed from tissues. They are multicellular. e) Symmetry: They are bilaterally symmetrical.f) Germ layers: They are triploblastic animals with three germ layers in embryonic stage.g) Segmentation: These animals are asegmented.h) Digestive tract: They have a complete digestive tract. The food enters from the mouth and excretes out from the anus.i) Sexual orientation: They are unisexual or dioecious animals. Male and female are separate.j) Systems:i. Reproductive system: They reproduce sexually only. They have internal fertilization. ii. Excretory system: Excretion takes place through protonephridia or flame cells.iii. Nervous system: Bundle of nerves and two nerve cords are present.iv. Respiratory system: Respiratory system is absent. They respire from general body surface.v. Circulatory system: They do not have circulatory system.Examples: ascaris, hookworm, pinworm, trichinella, roundworm etc.male femaleAscaris Hookworm WuchereriaFACTS WITH REASONSA pinworm is an aschelminth but not an annelid. A pinworm is called an aschelminth because it has an unsegmented body. An annelid must have a metamerically segmented body which is absent in a pinworm. So, it is not called an annelid. 5. Annelida [Latin: 'annelus' – ring]Annelida is the phylum of animals with metamerically segmented body. a) Body structure: The body is round, flexible, slender, tapering , cylindrical and elongated. b) Special feature: They are metamerically segmented animals with both parasitic and nonparasitic nature. Parasitic annelid suck blood. Some of them are ectoparasite. They suck blood from outside of body.

32 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 33c) Locomotion: The locomotion takes place with the help of setae (earthworm), parapodia (sandworm) and sucker (leech).d) Body organization: They are multicellular. They have organs developed into few systems. They have a strong regeneration ability.e) Symmetry: They are bilaterally symmetrical.f) Germ layers: These are triploblastic animals with three germ layers in embryonic stage.g) Segmentation: Their body is metamerically segmented internally as well as externally.h) Digestive tract: They have a complete digestive tract. The food enters from the mouth and excretes from the anus.i) Sexual orientation: They are both unisexual (polychaete) and bisexual (earthworm) animals.j) Systems:i. Reproductive system: They reproduce sexually and in some species asexually.ii. Excretory system: Excretion takes place through nephridia or excretory tubes present in their segments.iii. Nervous system : They have a bundle of nerves, two nerve cords and a nerve ring.iv. Respiratory system: They breathe through their moist skin.v. Circulatory system: The circulatory system is well developed. They have red blood due to presence of haemoglobin.k) They live in water, under the moist soil, in swamps and moist places.Examples: earthworm, leech, nereis (sandworm), bobbit worm etc.Earthworm Leech Nereis6. Arthropoda [Greek: 'arthros' – jointed, 'podos' – feet]Arthropods are bilaterally symmetrical and triploblastic animals which have multiple paired feet. The phylum arthropoda is the largest phylum which includes 84% of all known species of animals. They are found everywhere in the earth. It could be aquatic, terrestrial and aerial. They live in any type of climate and altitude. Some of their common features are:a) Special feature: They have jointed appendages (i.e. legs, antennae, mouth parts) due to which they are called arthropods meaning jointed feet in Greek. The body is triploblastic and segmented. It is divided into head, thorax and abdomen. Some arthopods have cephalothorax. The structure made from fusion of head and thorax is called cephalothorax. The body of arthopods is covered with dry scaly exoskeleton made of chitin. They often have sensitive and projected appendage known as antennae. The antennae help them in sensing food, prey, weather and their enemies. The head contains compound eyes, simple eyes, a mouth and an antenna. They have six pairs or more pairs of legs that grow from the thorax. They may or may not have wings.

34 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 35b) Locomotion: The locomotion takes place with the help of legs, wings or both. The jointed legs and wings grows from thorax. Some of them do not have wings. Some of them have one pair of wings or two pair of wings.c) Symmetry: They are bilaterally symmetrical.d) Germ layers: They are triploblastic animals with three germ layers in embryonic stage.e) Segmentation: They have segmented body.f) Digestive tract: The digestive tract is complete. The food enters from the mouth and excretes from the anus.g) Sexual orientation: They are generally unisexual.h) Systems:i) Reproductive system: They reproduce sexually. Their abdomen contains genitals. Males and females are separate. They are mostly unisexual.ii) Respiratory system: The respiration takes place through body surface, gills, trachea, book gills or book lungs.iii) Excretory system: Excretion takes place through malphigian tubules and glands.iv) Nervous system: They have a bundle of nerves, two nerve cords and a nerve ring. Examples: prawn, crab, spider, scorpion, centipede, butterfly, millipede, honey bee, spider, grasshopper etc.There are four classes in phylum Arthropoda. Which are divided on the basis of the number of legs and habitat. They are crustacea, insecta, arachnida, myriopoda.Prawn Butterfly Spider MillipedeFACTS WITH REASONSHoney bee belongs to the phylum Arthropoda and class Insecta.Honey bee belongs to phylum Arthropoda because it has jointed legs emerging from the thorax. It belongs to the class Insecta because it has six legs. 7. Mollusca [Latin: 'molluscus' – soft]The animals of phylum mollusca have soft-body. They mostly live on moist land, fresh water and marine water. They are both free living and parasitic. Their salient features are explained below:a) Body structure: The body is soft, flexible and often covered by hard shell called mantle. It provides protection. They have exoskeleton made of calcium. They hide inside it when touched. They have well developed digestive system and circulatory system.b) Special feature: Their body is divided into three parts: head, visceral mass (with shell) and muscular foot. The head has eyes and tentacles which helps in sensing the surrounding.c) Locomotion: The locomotion takes place with the help of muscular foot or cephalic arms. Terrestrial mollusks glide on land using muscular foot. Muscular foot also helps aquatic mollusks in swimming in water.

34 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 35d) Body organization: They have organs developed into systems and are multicellular. e) Symmetry: Some of them are bilaterally symmetrical. Most of them are asymmetrical. f) Germ layers: They are triploblastic animals. g) Segmentation: Their body is unsegmented.h) Digestive tract: The digestive tract is complete. The food enters from the mouth and excretes waste from the anus.i) Sexual orientation: They are both unisexual and bisexual animals.j) Systems:i) Reproductive system: They reproduce sexually by internal fertilization.ii) Excretory system: Excretion takes place through metanephridia or excretory ducts.iii) Nervous system: They have a bundle of nerves, two nerve cords and a brain.iv) Respiratory system: They use moist body surface or pulmonary sac or gills for breathing.Examples: octopus (devil fish), snail, slug, squid, sepia (cuttle fish), pila, unio etc. SnailOctopusSlugSepiaPilaSquid8. Echinodermata [Greek: 'echinos' – spiny, 'derma' – skin]Echinoderms are exclusively marine animals. So they are not found in Nepal in natural waters. Their body features are given below:a) Body structure: The body is spherical, star-shaped , elongated, globular or cylindrical. Mouth is present in ventral side. b) Special feature: They are exclusively marine organisms with no head. They have water vascular system. Their body is spiny to attack the prey and defend against enemies. Those spines are hard and made of calcium. So, it is called calcareous spines.c) Locomotion: The locomotion takes place with the help of tube feet.d) Body organization: They have organs developed into systems and are multicellular. e) Symmetry: Their larvae are bilaterally symmetrical while the adults are radially symmetrical.f) Germ layers: They are triploblastic.g) Segmentation: Their body is unsegmented.h) Digestive tract: Digestive tract is complete. They possess mouth, stomach, intestine and anus.i) Sexual orientation: They are mostly unisexual. MEMORY TIPSEchinodermata respires through gills.

36 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 37j) Systems:i) Reproductive system: They mostly reproduce sexually but are also able to reproduce by regeneration.ii) Excretory system: Excretion takes place through anus.iii) Nervous system: A bundle of nerves arising from a nerve ring is present.Examples: starfish, sea urchin, sea cucumber, brittle star, etc.Starfish Sea urchin Sea cucumber Brittle starChordatesThe group chordates include only one phylum: chordata.Phylum ChordataChordates are animals which possess a notochord in the embryonic stage of their life. A notochord is a dorsal (towards the back of animal) structure of rod-like cells that runs from head to tail in the embryonic stage. The sub-phyla of chordata phylum are Hemichordata, Urochordata, Cephalochordata, and Vertebrata. Notably, the protochordates, including Urochordata, Cephalochordata, and Hemichordata, lack the transformation of the notochord into a vertebral column. They are less developed than Vertebrata. In the sub phylum Vertebrata, the notochord transforms into a sophisticated vertebral column during the adult stage. Chordates share common traits such as the presence of a dorsal nerve cord above the notochord during embryonic stages, pharyngeal gill slits, a post-anal tail in early development, and a closed circulatory system. Noteworthy features like a hollow, tubular nervous tissue within the vertebral column and an endoskeleton inside muscular tissues. Chordates' closed circulatory system ensures the flow of blood within blood vessels. They are bilaterally symmetrical and triploblastic. Balanoglossus-Hemichordate Herdmania-Urochordate Amphioxus-A CephalochordateSub-phylum VertebrataThis sub-phylum includes all the vertebrates. Vertebrates are those animals that have a backbone or vertebral column. The backbone helps to protect the vertebral column enclosed inside it. The common characteristics of sub-phylum vertebrata are as follows:

36 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 37i. The bones and the vertebrae surround the spinal cord. ii. They have a skull that protects their brain.iii. Notochord is present in the earlier stage of their life which converts into vertebral column later.iv. They have an endoskeleton made up of bones and cartilage.v. A dorsal nerve cord is present above the notochord in the embryonic stage.vi. Pharyngeal gill slits and post anal tail are present in the embryonic stage. vii. The circulatory system is closed type. Some of them have two chambers in the heart. Some of them have three or four chambers in the heart.viii. They breathe by lungs or gills or moist skin.ix. Some of them are oviparous. They lay eggs and produce children through eggs. Some of them are viviparous. They give direct birth to children.x. Their body is bilaterally symmetrical. xi. Some of them are cold-blooded animals whose body temperature is not constant and keeps changing based on the temperature of the environment. They are also called poikilothermic animals. However, some of them are warm-blooded animals. Their body temperature is fixed and does not change with the temperature of the environment. Their body temperature is slightly greater than the average temperature of the environment. They are also called homeothermic animals. Project WorkObserve in your surrounding and find out the different examples of vertebrata. Write their names and discuss in the class.FACTS WITH REASONSAll vertebrates are chordates but all chordates are not vertebrates, why?All vertebrates are chordates but all chordates are not vertebrates because all vertebrates have a notochord in the embryonic stage of their life while all chordates do not possess vertebral column.The sub-phylum Vertebrata is divided into five classes namely: Pisces, Amphibia, Reptilian, Aves and Mammalia.Class Pisces (fishes) (Latin: 'piscis' – a fish)Pisces represents a category of vertebrates adapted to aquatic environments and characterized by specific anatomical features:i) Their bodies are structured into head, trunk, and tail, typically adorned with durable, water-resistant scales. The streamlined tapering on both sides is a common trait.ii) These creatures are cold-blooded, experiencing changes in body temperature in response to variations in their surroundings.iii) Locomotion is facilitated through the use of paired and unpaired fins and a tail.iv) Gills serve as the primary respiratory organs for breathing. Gills are present on the lateral side of the body. v) Their circulatory system consists of a two-chambered heart, featuring one atrium and one ventricle.MEMORY TIPSThe fish are laterally flat, streamlined and elongated.

38 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 39vi) Reproduction typically involves laying eggs, a process known as oviparous reproduction. However, some species are viviparous. They are unisexual organisms. vii) External fertilization is the norm, although exceptions exist, such as sharks. Sharks have internal fertilization. viii) They have air sacs in their body, that help them to float. Examples: Dog fish, saw fish, great white shark, rohu, katla, sea horse, flying fish, etc.Sea horse Shark RohuClass Amphibia (Greek: 'Amphi'- dual, 'bios' - life)The amphibians are those creatures that can breathe both on land and inside water. The females lay eggs inside water which hatch and develop gradually into an adult in different stages. Some of its characteristics are:i) Body is differentiated into head and trunk. They have two pairs of limbs with webbed feet for walking and swimming. Some of them have a tail. The skin is moist and doesn’t contain scales.ii) Body temperature changes with the change in the temperature of the surroundings, i.e. they are cold-blooded animals.iii) Locomotion takes place with the help of webbed feet. The limbs are pentadactylated, i.e. with five digits.iv) Breathing occurs with the help of lungs in air, skin in water and gills in tadpole stage. Tadpoles are young frogs hatched from eggs. They appear like fish and has gills to breathe.v) Heart is three-chambered (two atria and one ventricle).vi) Reproduction takes place by laying eggs i.e. they are oviparous. Sexes are separate.vii) Amphibians are oviparous. Female amphibians lay eggs in water and male amphibians release sperm in water. The sperm and the egg fuse in the water and change into a zygote. It is called external fertilization. It is common in amphibians. Examples: Frog, toad, salamander, tree frog (hyla), ichthyophis etc.Salamander Toad Frog IchthyophisMEMORY TIPSAmphibians are unisexual. They need water for fertilization so they are called amphibians.

38 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 39FACTS WITH REASONSTadpoles have gills. Tadpoles have gills to breathe underwater because they live in water. It also suggests that they evolved from fishes. Class Reptilia: (Latin: 'repere or reptum' - to creep or crawl)Reptiles are those creatures that crawl on the ground with their ventral surface. Some of its characteristics are:i) Body is differentiated into head, neck trunk and tail. They have two pairs of limbs with webbed feet for walking and swimming. The skin is dry and contains tough scales. They do not have ear holes. ii) Body temperature changes with the change in the temperature of the surroundings, i.e. they are cold-blooded animals.iii) Locomotion takes place with the help of limbs (except in snakes and lizards like glass lizard)iv) Reptiles spend lots of time in the water but they breathe through their lungs. v) Heart is three-chambered except in crocodile which has four chambered heart.vi) Reproduction takes place by laying eggs i.e. they are oviparous. Sexes are separate. It means they are unisexual.vii) They have internal fertilization. The male gamete and the female gamete of the reptile fuse inside the body of the female to form a zygote. Then the fertilized eggs are laid. Examples: crocodile, tortoise, turtle, wall lizard, garden lizard, snake like Cobra, krait etc.Wall lizardCrocodileTurtleTortoiseSnakeClass Aves: (Latin: 'avis' - bird)Aves or birds are animals that spend most of the time in air. They are well modified for aerial adaptation. Salient features of aves are:i) Body is differentiated into head, neck trunk and tail. Their forelimbs or wings are modified for flying and hind limbs for walking, grabbing or swimming. They have a toothless beak modified for their feeding habit. They have air sacs in their body that helps in floatation. They have feathers to keep them warm and help in flying.MEMORY TIPSAquatic reptiles such as turtles have to come back to land for breathing because they do not have gills.

40 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 41ii) Bones are light in weight, air-filled, hollow and reduced. Such bones are known as pneumatic bones.iii) Body temperature does not change with the change in the temperature of the surroundings, i.e. they are warm-blooded animals.iv) Locomotion takes place with the help of wings (in air) and legs (on land). Legs have five digits with claws (pentadactylated).v) Breathing occurs with the help of lungs.vi) Heart is four chambered (two auricles and two ventricles).vii) Reproduction takes place by laying eggs i.e. they are oviparous. They are unisexual.viii) Fertilization is internal.Examples: parrot, sparrow, pigeon, crow, owl, vulture, eagle, duck, lophophorus, hen, peacock etc.Peacock Ostrich Sparrow PigeonFACTS WITH REASONSAves have pneumatic bones.Aves have pneumatic bones because it helps them to fly by decreasing density and decreasing weight. Class Mammalia: (Latin: 'mamma' - breast)Mammals are the largest group of vertebrates on earth. They are the most intelligent and advanced creatures. Their chief characteristics are as follows:i) Body is divided into head, neck, trunk and tail (if present). Hairs are present on the body. They have externally projected ears called pinnae.ii) Babies of all mammals suckle the milk of their mothers after birth.iii) Body temperature does not change with change in the temperature of the surroundings, i.e. they are warm-blooded.iv) Locomotion mostly takes place with the help of two pairs of limbs (except in humans).v) They breathe by lungs. Aquatic mammals also need to come to the surface of the water and breathe using their lungs because they do not have gills.vi) Heart is four chambered (two atria and two ventricles).vi) Brain has a distinct region called neocortex. Which is responsible for higher forms of intelligence.MEMORY TIPSPisces and amphibian show external fertilization whereas reptiles, aves and mammals show internal fertilization.MEMORY TIPSWhale and bat are mammals because they give direct birth and suckle the babies.

40 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 41vii) Reproduction takes place by giving birth to young ones directly except in monotremes. Sexes are separate. They are unisexual.viii) Fertilization is internal.Examples: Human, blue whale, dolphin, bat, kangaroo, duck-billed platypus, horse, cow etc. Dolphin Kangaroo MonkeyDuck-billed platypus Squirrel BatRelation of classification of organisms with evolution of life on the earthThe categorization of living organisms according to shared characteristics is referred to as classification. This system places simpler and more primitive organisms ahead of their more developed counterparts. For example, the kingdom Monera comprises unicellular prokaryotes, representing a more rudimentary life form compared to the unicellular eukaryotes in the kingdom Protista. This suggests an evolutionary progression from Monera to Protista and continues with Protista being simpler than the kingdom Fungi.This classification pattern aligns with the broader evolutionary process, wherein less complex organisms originate earlier than more complex organisms. Illustrating this, Pisces, with twochambered hearts, evolved before amphibians and reptiles, which possess three-chambered hearts. This correlation highlights the connection between the evolution of life and its classification on Earth. As we move through each level of classification, the number of species in a group decreases. When two species share the same genus, it often indicates a recent common ancestor in their evolutionary history, further supporting the notion of life evolving from simpler to more complex forms.In summary:i. Classification of living organisms is based on their evolutionary history.ii. There is a noticeable similarity between the closest divisions or classes of organisms, suggesting ongoing evolution.iii. Some organisms exhibit characteristics of two or more classes, providing evidence for the reality of evolution.iv. Different classes sharing common characteristics, such as cold-blooded oviparous traits in fish, amphibians, and reptiles, suggest a shared evolutionary ancestry.

42 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 43HOT SKILL HIGHER ORDER THINKING SKILL1. Although bats and whales have dissimilar characteristics, they belong to the same class.Although bats and whales have dissimilar characteristics they belong to the same class because both of them give direct birth and females feed milk to babies. 2. Suppose you found an organism in the meadow. List the way to identify the phylum of that organism.If we see a creature in the meadow, we can identify its phylum by observing its features.For example,i. If it has bones, it is Chordata.ii. If it has a cylindrical, segmented body with many rings, it is an annelida.iii. If it has a cylindrical, unsegmented body, without rings, it is aschelminthes. iv. If it is flat, ribbon-like, it is platyhelminthes.v. If it has a soft muscular body without bones, it is a mollusca.vi. If it is an invertebrate with many appendages, it is Arthropoda. Other phyla are either microscopic that cannot be seen or aquatic that cannot be found in a meadow. 3. Differentiate between jelly fish and cuttle fish. The differences between jelly fish and cuttle fish are:SN Jelly fish SN Cuttlefish 1 They have tissues but no organs. 1 They have organs and systems. 2 They have coelenteron cavity, tentacle and hypostome.2 They have visceral mass, mantle and muscular feet. 3 It belongs to the Phylum Coelenterata. 3 It belongs to the Phylum Mollusca. 4. Tabulate the differences between moss and clubmoss.The differences between moss and clubmoss are:SN Moss SN Clubmoss1 Moss is a bryophyte. It is less developed than clubmoss.1 Clubmoss is a tracheophyte. It is more developed than the moss.2 It is called amphibian plant because it needs water for fertilization. 2 It is not an amphibian plant. 3 It does not have a vascular bundle. 3 It has a vascular bundle.5. All vertebrates are chordates but all chordates are not vertebrates. Vertebrates are organisms whose notochord are replaced by the vertebral column. So, a vertebrate is a chordate. However, some species of chordates do not develop vertebral columns so they cannot be vertebrates. 6. Is observation of only the flowers the right way to identify monocotyledon? Give reasons. We can know a monocotyledon plant by looking at flowers because the petals of flowers of monocotyledons are in multiple of three. However, it would be wise to look at other characteristics to identify monocotyledon such as parallel venation of the leaf, only one cotyledon in the seed and a fibrous root system.

42 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 437. Coelenteron of hydra also called a gastrovascular cavity. The coelenteron of hydra is called the gastrovascular cavity because it helps in the digestion of food and distribution of nutrients. 8. Classify human beings Kingdom : Animalia Phylum : Chordata Sub-phylum : Vertebrata Class : Mammalia Type : Human 9. What do reptiles and Pisces have in common? Write in three points. The common features between reptiles and Pisces are given below:i. Both reptiles and Pisces are the classes of Vertebrata. ii. They have scales on their body.iii. They are cold-blooded organisms.10. Study the given diagram and answer the following questions.i. Write the phylum and class of the given organisms.Name : WhalePhylum : Chordata Class : Mammalia Name : Shark Phylum : ChordataClass : Pisces ii. Write similarities and differences between these organisms.Similarities between sharks and whales are:a. Both of them are aquatic. b. Both of them have streamlined bodies.c. Both are carnivorous.d. Both of them locomote by fins.Differences between sharks and whales area. Whales are viviparous but sharks are oviparous.b. Whales breathe by lungs but sharks have gills to breathe.c. Whales are warm-blooded but sharks are cold-blooded.d. Whales are mammals but sharks are fish.iii. How do these organisms support evolution?Sharks are fish but whales are mammals. These two different species have adapted to survive in an aquatic ecosystem. Their body despite different anatomy appears the same. For, example, the fins of whales and the fins of shark are anatomically different but appear same and both help to swim. These are analogous organs. These organs suggest that organisms can evolve based on their environment. (a)(b)

44 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 454 STEPS EXERCISE EXERCISESTEP11. Multiple choice questions a. Algae are thallus. What does it mean? i. it has a root, stem and leaf ii. it has rhizoids, rhizomes and fronds iii. it has a rhizome and a leaf iv. it has no differentiable root, stem and leafb. Why does pine belong to gymnosperm?i. needle-like leaf, naked seed, rough bark ii. needle-like leaf, enclosed seed, rough barkiii. flat and broad leaf, enclosed seediv. narrow leaf, parallel venation, spongy stem c. Which of the following has a backbone?i. shellfish ii. fishiii. starfish iv. jelly fish d. Which set of the following classes are closely related? i. Pisces, Amphibia, Mammalia ii. Amphibia, Reptilia, Aves iii. Pisces, Reptilia, Aves iv. Amphibia, Aves, Mammalia e. Shefali observed two plants, she found that both plants needed water for fertilization and both were non-flowering. She also found that plant A is nonvascular but plant B is vascular. Based on this observation. Which statement is true?i. Plant A has a shorter gametophyte whereas plant B has longer gametophyte. ii. Plant A is is fern and plant B is moss. iii. Plant A can be tall whereas plant B is short.iv. Plant A has a shorter sporophyte whereas plant B has longer sporophyte. f. Which set of features best describes Plantae? i. eukaryotic cell, cell without cell wall, heterotrophs ii. eukaryotic cell, cell with cell wall, heterotrophs iii. eukaryotic cell, cell with cell wall, autotrophs iv. eukaryotic cell, no cell wall, saprotrophs g. Which of them is kingdom Protista? A Bdo not have membrane bound organellehas membrane bound organellesunicellular organismi. A ii. Biii. A as well as B iv. Neither A nor B

44 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 45h. Eleonor watched a flower and said it was a monocotyledon. How could she tell?i. By looking at the colour of flowers. Monocotyledons have pink, red and white flowersii. By looking at the size of the petals of flowers. Petals of flowers are 3 mm to 3 cm long.iii. By counting the number of petals. Petals are in the multiple of three in a monocot flower.iv. By counting the number of cotyledons. Monocotyledon flower has one cotyledon. i. Study the given dialogue.Arya: The stems of the plants have nodes. Leaves or branches grow from them. Elle: I have noticed that nodes are at regular intervals in the maize plant.Eleonor: Nodes are not at equal intervals in the gram plant. Who is right and who is wrong in the above dialogue?i. Arya, Elle and Eleonor are correct.ii. Elle is correct but Arya and Eleonor are wrong. iii. Arya is correct but Elle and Eleonor are wrong.iv. Eleonor is correct but Arya and Elle are wrong.j. Why are these two organisms kept in the same phylum? i. both of them have the same characteristics ii. both of them have a vertebral column iii. both of them had notochord during the embryonic stage iv. both of them are eukaryotic, multicellular and heterotroph without cell walla. iv b. i c. ii d. ii e. iv f. iii g. ii h. iii i. i j. iiiAns of MCQSTEP22. Very short questions a. The following chart shows the group of four plants. In which group does fern belong?Absence of vascular tissue Presence of vascular tissue Reproduce by spores A CReproduce by seeds B Db. Why are club mosses more advanced than the mosses? c. A plant is observed and findings are written below. Which division of plant is it? Give an example. (a) (b)

46 cl aS Sification of living t HingS Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Approved by the Curriculum Development Centre, Sanothimi, Bhaktapur Modern Concept Science & Technology - 10 47Features The body is differentiated into rhizome, rhizoid and leaf Vascular tissue Alternation of generation Seen Not seen seen d. Which phylum liver fluke, otoplana and diplozoon belong? e. What is the evolutionary relationship between fish and frogs?f. Euglena is a unicellular organism with chlorophyll. Which kingdom should it belong to?g. Write one main characteristic of each of the Pinus.h. Write a difference between sporophyll and tropophyll. i. Which class of plant possess this kind of leaf? STEP33. Short questions a. Horsetail is a cryptogam. The pine tree has a cone but no fruit and the maize plant has flowers and fruit. Despite having so many different features, they still belong to the same kingdom. Why? b. Classify the following organisms shown in the diagram 'a' and 'b'. Which one is the more advanced among them?(a) (b)c. Write any two differences between bryophytes and pteridophytes. d. Which one of the following is spirogyra? Why? Thallus Non-thallus Autotroph A BHeterotroph C De. Give the name and division of the plant with the following characters and write one more character of it:(i) Seeds are enclosed in fruits (ii) Plants with fibrous rootsf. All chordates are not vertebrates but all vertebrates are chordates. Justify. g. An organism has multiple pores (ostia) in the body that can collect food and a large pore (osculum) to remove waste. Which phylum does it belong to?