Class 10 - Science Five-Year Question Collection (2021-2025) Important reference for Public Exam 2026

Class 10 Science

Five-Year Question Bank (2021-2025)

UNIT 1: LAWS OF MOTION

2 MARK QUESTIONS

1. Define inertia. Give its classification. (Apr'2023)
2. What is mechanics? Explain its branches.
3. What are the types of inertia?
4. Give any two examples of inertia. (Aug 2022)
5. Define linear momentum.
6. State Newton's law of motion. (Aug 2022)
7. State Newton's first law.
8. What is meant by force?
9. Classify the types of force based on their application. (Aug 2022)
10. Define resultant force.
11. Define impulse.
12. Name the law of motion used in flying of birds. Give another example for the same law. (PTA-2)

4 MARK QUESTIONS

1. Deduce the equation of a force using Newton's second law of motion. (Apr 2023)
2. Explain the various types of inertia with examples. (Apr 2024)
3. State Newton's universal law of gravitation and derive its mathematical expression. (Jul'2023)
4. Give the applications of universal law of gravitation. (Jun'2024)
5. Define moment of the force and moment of a couple.
6. Define 1 newton (N).
7. State Newton's Third law of motion.
8. Give any two examples of Newton's law of motion.
9. State Newton's second law of motion. (May'2022)
10. Classify the types of force based on their application.

7 MARK QUESTIONS

1. (a) (i) State and prove the law of conservation of linear momentum. (ii) State the principle of moments.
2. Application of Torque. Write short notes on gears. (Sep'2020)
3. Describe rocket propulsion. (Aug 2022)
4. Relation between g and G.
5. Differentiate mass and weight. (May'2022)
6. Explain the application of Newton's law of gravitation.

UNIT 2: OPTICS

2 MARK QUESTIONS

1. Differentiate Convex lens and Concave lens. (Jun 2024)
2. Why does the sky appear blue in colour? (Apr'2023)
3. Define refraction of light.
4. State First law of refraction.
5. State second law of refraction (Snell's law). (Aug 2022)
6. Define dispersion of light.
7. State Rayleigh's scattering law. (PTA-3)
8. Define lens.
9. What are the types of lens?
10. What is meant by Plano-convex lens?
11. What is meant by Plano-concave lens?
12. Why are traffic signals red in colour? (PTA-4)
13. What is the least count of travelling microscope?

4 MARK QUESTIONS

1. Differentiate the eye defects: Myopia and Hypermetropia. (Apr 2023)
2. List any four properties of light. (Jun 2024)
3. Explain the types of scattering.
4. Write note on Mie scattering, Tyndall scattering, Raman Scattering.
5. Explain images formed due to refraction through a convex and concave lens.
6. What are the applications of convex lenses? (Any two)
7. What are the applications of concave lenses? (Any two) (Sep'2021)
8. Write Lens formula.
9. Explain sign convention.
10. What are the causes of 'Myopia'? (GMQP-2019)
11. Explain simple microscope. What are the uses of simple microscope? (Sep'2020)

7 MARK QUESTIONS

1. (a) (i) What are the uses of convex lens? (ii) Define dispersion of light. (iii) Why are traffic signals red in colour? (iv) What is the least count of travelling microscope?
2. (b) (i) What is echo? (ii) State two conditions necessary for hearing an echo. (iii) What are the medical applications of echo? (iv) How can you calculate the speed of sound using echo? (Apr 2024)
3. (i) What is refractive index? (ii) Differentiate the eye defects Myopia and Hypermetropia.
4. (i) Distinguish between the resistivity and conductivity of a conductor. (ii) List the merits of LED bulb. (iii) How does an astronaut float in a space shuttle? (Jun'2024)
5. (a) (i) Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F. (ii) State Rayleigh's law of Scattering. (iii) Differentiate - Convex lens and Concave lens.
6. Explain the construction and working of a Compound microscope. (QY-2019)
7. Explain types of Telescopes. What are the advantages and disadvantages of telescope?

UNIT 3: THERMAL PHYSICS

2 MARK QUESTIONS

1. Define one Calorie. (Apr'2023)
2. What is a longitudinal wave? (Apr 2025)
3. What is coefficient of apparent expansion? (Apr'2024)
4. State Boyle's law. (Jun'2024)
5. Distinguish between real gas and ideal gas. (Jul'2025)
6. Define temperature.
7. Define absolute temperature.
8. Define thermal equilibrium.
9. Define thermal energy.
10. Define kilocalorie.
11. Define co-efficient of linear expansion. Write its equation. (PTA-1)
12. What is co-efficient of cubical expansion? (PTA-6)
13. What is co-efficient of superficial or areal expansion? (Sep'2020)

4 MARK QUESTIONS

1. Derive the ideal gas equation. (Apr 2025)
2. Explain the experiment of measuring the real and apparent expansion of a liquid with a neat diagram. (Jul'2025)
3. (i) State Boyle's law. (ii) Distinguish between real gas and ideal gas. (Jul'2023)
4. Write three fundamental law of gases. (QY-2019)
5. State Charles's law & formula.
6. State Avogadro's law & formula. (Sep'2021)
7. What is real gas?
8. Define ideal gas.

UNIT 4: ELECTRICITY

2 MARK QUESTIONS

1. Define the unit of Current. (Jul'2023)
2. Calculate the resistance of a conductor through which a current of 2 A passes, when the potential difference between its ends is 30 V. (Jun'2024)
3. A charge of 12 Coulomb flows through a bulb in 5 seconds. What is the current through the bulb? (Jul 2023)
4. Define electric current. Sl unit of current. (May'2022)
5. What is electric circuit.
6. What is direction of current.
7. Define electric potential & Sl unit.
8. Define volt.
9. State Ohm's law. (SRT-2022)
10. Define resistance of a conductor & SI Unit.
11. Define electrical resistivity.
12. Define electrical conductivity.
13. Define electric power & Sl unit.

7 MARK QUESTIONS

1. (i) State Joule's Law of Heating. (ii) An alloy of nickel and chromium is used as the heating element. Why? (iii) How does a fuse wire protect electrical appliances?
2. (i) What is a longitudinal wave? (ii) What is a nuclear reactor? Explain its essential parts with their functions. (Apr 2023)
3. With the help of a circuit diagram derive the formula for the resultant resistance of three resistances connected: a) in series and b) in parallel.
4. Explain about domestic electric circuits. (Sep'2020)
5. What are the advantages of LED TV? and List the merits of LED bulb. (PTA-6)
6. (i) What is meant by electric current? (ii) Name and define its unit. (iii) Which instrument is used to measure the electric current? How should it be connected in a circuit? (Apr'2025)

UNIT 5: ACOUSTICS

2 MARK QUESTIONS

1. Name any three animals which can hear ultrasonic vibrations. (Jul'2023)
2. What will be the frequency of the sound having 0.20 m as its wavelength, when it travels with a speed of 331 m $S^{-1}?$ (Jul'2025)
3. Define acoustics?
4. What is a longitudinal wave?
5. Write note on Audible waves.
6. Write note on infrasonic waves.
7. Write note on Ultrasonic waves. (Sep 2020)
8. Difference between sound and light.
9. Define reflection of sound.
10. State law of reflection.
11. Define Echoes.
12. What are the conditions necessary for hearing echo? (PTA-1)
13. Mention two cases in which there is no Doppler effect in sound? (Sep'2020)

4 MARK QUESTIONS

1. (a) What are the medical applications of Echo? (b) Name four animals, which can sense ultrasonic vibrations. (Jul'2025)
2. A source producing a sound of frequency 90 Hz is approaching a stationary listener with a speed equal to $(1/10)$ of the speed of sound. What will be the frequency heard by the listener? (Apr'2025)
3. (a) What do you understand by the term Ultrasonic Vibration? (b) What is meant by reflection of sound? (Apr'2023)
4. (i) Mention the two cases in which there will be no Doppler effect in sound. (ii) What is stellar energy? (Jun'2024)
5. Explain the reflection at the boundary of a denser medium.
6. Explain the reflection at the boundary of a rarer medium.
7. Explain the reflection at curved surfaces.
8. What are the application echoes? (May'2022)

UNIT 6: NUCLEAR PHYSICS

2 MARK QUESTIONS

1. Define radioactivity.
2. Define natural radioactivity.
3. Define artificial radioactivity or induced radioactivity.
4. Difference between natural radioactivity and artificial radioactivity. (Aug 2022)
5. Write the features of nuclear fission and nuclear fusion. (GMQP-2019)
6. Define curie.
7. Define Rutherford.
8. Define Becquerel.
9. Define Roentgen.
10. Write note on alpha decay.
11. Write note on Beta decay.
12. Write note on Gamma decay.
13. What is meant by Dosimeter.
14. Explain the uses of radioactivity in agriculture, medicine, industries, Archeological research. (May'2022)

4 MARK QUESTIONS

1. Compare the properties of alpha, beta and gamma radiations. (Jul 2023)
2. (a) State Soddy and Fajan's displacement law. (b) Give any two uses of radio isotopes in the field of Agriculture. (Jul'2025)
3. (a) Write any three features of natural and artificial radioactivity. (b) Name any two devices, which are working on the heating effect of current. (Apr 2024)

UNIT 7: ATOMS AND MOLECULES

2 MARK QUESTIONS

1. Define Atomicity. (Jul'2025)
2. Define Relative atomic mass. (Jul'2023)
3. Mention any two applications of Avogadro's Law. (Apr 2023)
4. State the findings of modern atomic theory. (Aug 2022)
5. Define mass number.
6. Define amu.
7. Define gram atomic mass. Give an example.
8. Define average atomic mass.
9. Define molecule. Explain classification of molecules.
10. Give any two examples for hetero diatomic molecule. (Aug'2022)

4 MARK QUESTIONS

1. Write the applications of Avogadro's Law. (Apr 2025)
2. Derive the relationship between Relative Molecular Mass and Vapour Density. (Jul'2025)
3. Write down the salient features of "Modern Atomic Theory". (Jun'2024)
4. Calculate the percentage of each element in Calcium Carbonate $[CaCO_{3}].$ [Atomic Mass $Ca=40;$ $C=12;$ $O=16]$ (Jul'2023)
5. (i) Calculate the number of moles in 27 g of Al. (ii) Calculate the gram molecular mass of $CO_{2}$. (Jun'2024)
6. Differentiate atom and molecule give an example. (May'2022)
7. State Avogadro's law & mathematical expression. Give an example. (Sep'2021)
8. Explain the application of Avogadro's law. (Sep'2020)
9. Define isotopes. Give an example.
10. Define isotones. Give an example.
11. Define isobars. Give an example.

UNIT 8: PERIODIC CLASSIFICATION OF ELEMENTS

2 MARK QUESTIONS

1. Fill in the blanks: (i) ______ forms the basis of modern Periodic table. (ii) The chief ore of Aluminium is ______. (Jul'2025)
2. State modern periodic law.
3. What is meant by modern periodic table.
4. Define atomic radius, metallic radius, covalent radius, ionic radius.
5. Define ionization energy.
6. Define electron affinity.
7. Define electronegativity.
8. Define metallurgy, minerals, ore, mining, Gangue, Flux, Slag, Smelting.
9. What are types of ore and example.

4 MARK QUESTIONS

1. (i) What is an alloy? (ii) State the reasons for alloying. (Apr'2025)
2. Explain the features of Periods in modern periodic table.
3. Explain the features of Groups in modern periodic table.
4. Write note on Hydraulic method (Gravity separation).
5. Write note on Magnetic separation method.
6. Write note on Froth floatation method.
7. Explain the physical properties of metals.
8. Explain the chemical properties of metals.
9. What are the ores of Aluminium. Explain extraction of Aluminium from Bauxite.
10. Name the acid the renders Aluminium passive. Why? (QY-2019)
11. What are the ores of Copper. Explain extraction of Copper from Copper pyrites.
12. What are the ores of Iron. Explain extraction of Aluminium from Haematite.
13. Chemical properties of Aluminium, copper, Iron.
14. What are the uses of Aluminium, copper.
15. What are types and uses of iron.
16. What is an amalgam?
17. What are reasons for alloying? (May'2022)
18. Write the methods of making alloys.
19. Why alloys as solid solutions.
20. What are the types of alloys?
21. Write the copper alloy and its uses.
22. Write the Aluminium alloys and its uses.
23. Write the Iron alloys and its uses.
24. What is corrosion? Types of corrosion, Methods of preventing corrosion. (Sep'2021)
25. What is rust? Give the equation for formation of rust. (Sep'2021)

UNIT 9: SOLUTIONS

2 MARK QUESTIONS

1. Why does the reaction rate of a reaction increase on raising the temperature? (Jun'2024)
2. True or False. (If false give the correct statement) (i) The pH of rain water containing dissolved gases like $SO_{3}$, $CO_{2}$, $NO_{2}$ will be less than 7. (ii) Noble gases are Diatomic. (Jun 2024)
3. If the pH of a solution is 4.5, find the value of its pOH. (Apr'2024)
4. Define solution.
5. Define solute & solvent.
6. Define dissolution.
7. Define binary solution. (QY-2019)
8. Define ternary solution.
9. Give a example each i) gas in Liquid; ii) solid in liquid iii) solid in solid iv) gas in gas. (PTA-1)
10. Define aqueous solution and example.
11. Define non-aqueous solution and example.
12. Define saturated solution and example.
13. Define unsaturated solution and example.
14. Define super saturated solution and example.
15. Define concentrated solution and dilute solution.
16. Define mass percentage & volume percentage.
17. State Henry's law.
18. Define water of crystallization. & hydrated salts.
19. Give an example of Hydrated salts.
20. Define Hygroscopy. Give an example of hygroscopic substances.
21. Define Deliquescence. Give an example of Deliquescence.

4 MARK QUESTIONS

1. (a) What happens when $MgSO_{4}\cdot7H_{2}O$ is heated? Write the appropriate equation. (b) Define: Solubility. (Apr'2024)
2. (i) Calculate the pH of $1.0\times10^{-4}$ molar solution of $HNO_{3}$. (ii) Define Hydrated salt. (Jun'2024)
3. Write notes on various factors affecting solubility. (Jul'2023)
4. (a) Name the acid that renders Aluminium passive. Why? (b) Calculate the number of moles in 1.51 x $10^{23}$ molecules of $NH_{4}Cl.$ (Apr 2024)
5. (a) Calculate the pH of 0.01 M solution of $HNO_{3}$. (b) A solution is prepared by dissolving 25 g sugar in 100 g of water. Calculate the mass percentage of solute. (Apr'2023)
6. Explain types of solution based on the physical state of the solute and the solvent.
7. What are the types of solution based on the type of solvent.
8. What are the types of solution based on the amount of solute.
9. Analyze the following statement about the formation of solution and explain with an example. "Like solvents dissolve Like solutes". (PTA-1)
10. The aquatic animals live more in cold region why? (PTA-5)
11. Explain the action of blue vitriol and Epsom salt.
12. 'A' is a blue coloured crystalline salt. On heating it loses blue colour and to give 'B'. When water is added. 'B' gives back to 'A'. Identify A and B. write the equation. (May'2022)
13. Explain hygroscopic substances and deliquescent substances with examples. (Aug 2022)
14. Classify the following substances into deliquescent, hygroscopic. Conc. Sulphuric acid, Copper sulphate penta hydrate, Silica gel, Calcium chloride and Gypsum salt. (Aug'2022)

7 MARK QUESTIONS

1. (a) (i) In what way hygroscopic substances differ from deliquescent substances? (ii) The aquatic animals live more in cold region. Why? (iii) Define volume percentage. OR (b) (i) Differentiate reversible and irreversible reactions. (ii) A solid compound 'A' on heating decomposes into gas 'B' and 'C'. On passing the gas 'C' through water, it becomes acidic. Identify A, B and C. (Apr 2025)
2. (a) Write notes on various factors affecting solubility. OR (b) Explain the factors influencing the rate of a Chemical reaction. (Jul'2025)
3. (a) (i) Under same conditions of temperature and pressure, if you collect 3 litre of $O_{2}$, 5 litre of $Cl_{2}$ and 6 litre of $H_{2}$: (A) Which has the highest number of molecules? (B) Which has the lowest number of molecules? (ii) Give the salient features of 'Modern Atomic theory'. OR (b) (i) How do detergents cause water pollution? (ii) An organic compound 'A' is widely used as a preservative and has the molecular formula $C_{2}H_{4}O_{2}$. This compound reacts with ethanol to form a sweet smelling compound 'B', then: (A) Identify the compound 'A'. (B) Write the chemical equation for its reaction with ethanol to form compound 'B'. (C) Name this process. (Apr 2024)
4. (a) (i) Write notes on: (1) Saturated Solution (2) Unsaturated Solution (ii) In what way hygroscopic substances differ from deliquescent substances? OR (b) (i) What is chemical equilibrium? What are its characteristics? (ii) Differentiate reversible and irreversible reactions. (Jul'2023)
5. (a) (i) Define: Atomicity. (ii) Calculate the percentage of sulphur in $H_{2}SO_{4}$ (iii) In what way hygroscopic substances differ from deliquescent substances. OR (b) (i) Differentiate reversible and irreversible reaction. (ii) What is neutralization reaction? Give an example. (iii) Give any three characteristics of homologous series. (Apr'2023)

UNIT 10: TYPES OF CHEMICAL REACTIONS

2 MARK QUESTIONS

1. State two conditions necessary for rusting of iron. (Apr'2025)
2. What is rust? Give the equation for the formation of rust. (Apr 2024)
3. (i) What is rust? Give the equation for the formation of rust. (ii) State two conditions necessary for rusting of iron. (Jul'2023)
4. Define balanced chemical equation and example.
5. Define combination reaction and example.
6. Define combination reaction. With one example for an exothermic combination reaction. (May'2022)
7. Define decomposition reaction and example.
8. Define thermal decomposition reaction and example. (Thermolysis reaction) (Sep'2021)
9. Define electrolytic decomposition reaction and example.
10. Define photo decomposition reaction and example.
11. Define single displacement reaction and example. (Sep'2020)
12. Define combustion reaction and example.
13. Define precipitation reaction and example.
14. Define Neutralization reaction and example.
15. Define reversible reaction and example.
16. Define irreversible reaction and example.
17. Define rate of a reaction.
18. Define ionic product of water & mathematical expression.
19. Define pH an expression of pH.

4 MARK QUESTIONS

1. (i) Match the following: (a) Co-60 - Cancer (b) I-131 - Thyroid disease (c) Na-24 - Function of Heart (d) C-14-Age of Fossil (ii) Use the analogy to fill in the blank. 1. Spontaneous Process: Natural Radioactivity :: Induced Process: ______ 2. Nuclear Fusion: Extreme temperature :: Nuclear Fission: ______ (Jul'2023)
2. What are classes of combination reaction and give an example.
3. Explain the types double displacement reaction with examples. (Sep'2020)
4. Differences between combination and decomposition reaction.
5. Classify the following reactions based on rearrangement of atoms and justify your answer a) $2KClO_{3} \rightarrow 2KCl+3O_{2}$ b) $Zn+CuSO_{4}\rightarrow ZnSO_{4}+Cu$ c) $2Mg+O_{2}\rightarrow2MgO$ d) $Na_{2}SO_{4}+BaCl_{2}\rightarrow BaSO_{4}+2NaCl$ (PTA-1)
6. Differences between reversible and irreversible reactions. (Aug'2022)
7. Explain factors influencing the rate of a reaction.

UNIT 11: CARBON AND ITS COMPOUNDS

2 MARK QUESTIONS

1. Match the following: Functional group -OH- (iii) Alcohol, Heterocyclic compounds - (iv) Furan, Unsaturated compounds - (v) Ethene, Soap (ii) Potassium Stearate, Carbocyclic compounds - (i) Benzene (Apr 2025)
2. Name the simplest ketone and give its structural formula. (Jul'2023)
3. Find the mass percentage composition of methane $(CH_{4})$. (Apr'2025)
4. How do detergents cause water pollution? (Jul'2025)
5. Explain General characteristics of organic compounds.
6. Classify the following compounds based on the pattern of carbon chain and give their structural formula: i) Propane ii) Benzene iii) Cyclobutane iv) Furan. (May'2022)
7. What is meant by hydrocarbon? How are classified?
8. How to identify saturated and unsaturated compounds.
9. Define functional groups? What is the functional group of alcohols, aldehydes, ketones, carboxylic acids, ester, ether.
10. Write the functional group and the suffix used for the following class of compounds. (May'2022)
11. Define homologous series. Characteristics of homologous series.
12. Define fermentation. Give an example.

4 MARK QUESTIONS

1. Differentiate Soaps and Detergents. (Jul'2025)
2. Explain the mechanism of cleansing action of soap. (Apr'2023)
3. (a) Write the structural formula for Cyclobutane. (b) The Molecular formula of an alcohol is $C_{4}H_{10}O$. The locant number of its -OH group is 4. (i) Draw its structural formula. (ii) Give its IUPAC name. (iii) Is it Saturated or Unsaturated? (Jul'2025)
4. Explain Characteristics of hydrocarbons.
5. Applying IUPAC rules, derive the structural formula of the following compounds. a) Pentanoic acid. b) 2-methyl-butan-2-ol. (PTA-2)
6. Explain manufacture of ethanol from molasses.
7. Explain chemical properties of ethanol.
8. Explain uses of ethanol. (Sep'2021)
9. Explain preparation, physical properties, chemical properties and uses of ethanoic acid.
10. Explain uses of organic compounds in daily life.
11. Define soap and explain types of soap.
12. Explain manufacture of soap. (Kettle process)
13. Explain the effect of hard water on soap.
14. Define Detergents and preparation of detergents.
15. Explain advantages and disadvantages of Detergents.
16. Explain why micelles formation take place with a diagram when soap is added to water? (PTA-5)

7 MARK QUESTIONS

1. (a) (i) How is ethanol manufactured from sugarcane? (ii) Define the term solution. (i) Differentiate soaps and detergents. (ii) What is chemical equilibrium? What are its characteristics? (Jun'2024)

UNIT 12: PLANT ANATOMY AND PLANT PHYSIOLOGY

2 MARK QUESTIONS

1. What is photosynthesis and where in a cell does it occur? (Jun'2024)
2. Draw and Label the structure of oxysomes. (Jul'2023)
3. What is meant by Tissues?
4. What are tissue system in plants.
5. What is meant by plastids.
6. What are the types of plastids?
7. What are the functions of chloroplast.
8. What is meant by Aerobic respiration.
9. Write note on anaerobic respiration.

4 MARK QUESTIONS

1. (a) What is Respiratory Quotient? (b) Why should the light dependent reaction occur before light independent reaction during photosynthesis? (Apr'2024)
2. Write the dental formula of rabbit. (Apr 2024)
3. What is transpiration? Write the importance of transpiration. (Jun'2024)
4. Write the physiological effects of Gibberellins. (Jun 2024)
5. (a) Name the three basic tissue systems in a flowering plant. (b) What are the factors affecting photosynthesis? (Apr'2023)
6. Explain Tissue system and its functions.
7. What are the functions of Dermal tissue system.
8. Write note on ground Tissue system.
9. What is Vascular bundle? (PTA-1)
10. Explain Vascular Tissue system.
11. Explain Internal structure of Dicot Root (Bean) (PTA-6)
12. Explain Internal structure of Dicot Root (sunflower)
13. Differences between Dicot and Monocot root. (Sep'2020)
14. Explain internal structure of Dicot (mango)
15. Explain structure of chloroplast.
16. Draw the structure of mitochondria and label the parts (QY-2019)
17. Write note on photosynthetic pigments?
18. Write note on role of sunlight in photosynthesis.
19. Write the reaction for photosynthesis. (May'2022)
20. What are factors affecting Photosynthesis. (Aug 2022)

7 MARK QUESTIONS

1. (a) Differentiate the following: (i) Monocot root and Dicot root (ii) Aerobic and Anaerob respiration. OR (b) (i) Explain the structure of a chromosome. (ii) Distinguish between somatic gene therapy and germ line gene therapy. (Apr'2025)
2. (a) (i) Write the reaction for photosynthesis. (ii) Draw and label the structure of oxysomes. (iii) Write a short note on mesophyll. OR (b) (i) Explain the types of Chromosomes based on the position of Centromere. (ii) Discuss the importance of biotechnology in the field of Medicine. (Jul'2025)

UNIT 13: STRUCTURAL ORGANISATION OF ANIMALS

2 MARK QUESTIONS

1. List out the parasitic adaptations in leech. (Apr 2023)
2. How does leech respire? (PTA-1)
3. How is diastema formed in rabbit? (PTA-6)
4. Why is the teeth of rabbit called heterodent? (PTA-4)
5. What are the glands embedded in the Rabbit skin to regulate the body temperature? (PTA-3)

4 MARK QUESTIONS

1. How does locomotion take place in leech? (Apr'2025)
2. (a) How does leech suck blood from the host? (b) How is diastema formed in rabbit? (Jul'2025)
3. How are Arteries and Veins structurally different from one another? (Apr'2024)
4. Write the dental formula of rabbit. (GMQP-2019)
5. Why are the rings of cartilages found in trachea of rabbit? (Sep'2020)
6. How is the digestive system of rabbit suited for herbivorous mode of feeding? (PTA-3)

UNIT 14: TRANSPORTATION IN PLANTS AND CIRCULATION IN ANIMALS

2 MARK QUESTIONS

1. What is the importance of valves in the heart? (Apr 2025)
2. Why is sinoatrial node called as pacemaker of heart? (Apr'2024)
3. What are the parts of the hind brain? (Apr'2024)
4. Define diffusion.
5. Write note on active transport.
6. Define osmosis.
7. What is meant by plasmolysis & imbibition?
8. Draw and explain root tip with Root Hairs.
9. What are components of Blood?
10. What are the Agranulocytes in blood?
11. Guard cells are responsible for opening and closing of stomata. (Sep'2021)
12. Mature RBC in mammals do not have cell organelles. (PTA-4)
13. What is cohesion? (PTA-1)
14. What is the circulation in man referred to as double circulation? (PTA-1)

3 MARK QUESTIONS

1. (a) Why is Euploidy considered to be advantageous to both plants and animals? (b) Classify Neurons based on its structure. (Apr 2024)
2. (i) Define Stimulus. (ii) Name the parts of the hind brain. (Jul'2025)
3. Enumerate the functions of blood. (Apr'2023)
4. Write note on Apoplast pathway.
5. Write note on Symplast pathway.
6. Define transpiration pull. (Aug 2022)
7. What is the importance of Transpiration? (Aug 2022)
8. Draw and label the parts of process of Transpiration. (Aug 2022)
9. Write note on Root pressure.
10. Write note on uptake of minerals.
11. Write note on translocation of mineral ions?
12. Write note on Phloem transport.
13. Write note on translocation of sugars.
14. The movement of substances in the phloem can be in any direction (PTA-4)
15. Minerals in the plants are not lost when the leaf falls. (PTA-2)
16. Differentiate Artery and Veins (PTA-5)
17. Differentiate Systemic and pulmonary circulation? (PTA-2)
18. Explain distribution of Antigen and antibody in different blood groups.
19. Who discovered Rh factor? Why was it named so? (PTA-6)
20. How are arteries and veins structurally different from one another? (PTA-5)

5 MARK QUESTIONS

1. (a) (i) What are synthetic auxins? Give an example. (ii) With a neat labelled diagram, describe the parts of the typical angiospermic ovule. OR (b) (i) Who is called the "Father of Indian Green Revolution"? (ii) Differentiate between out-breeding and in-breeding. (iii) Differentiate between Type-l and Type-II Diabetes mellitus. (Apr 2024)

UNIT 15: NERVOUS SYSTEM

2 MARK QUESTIONS

1. What does CNS stand for? (Jul'2023)
2. What are the structures involved in the protection of brain? (Apr'2023)
3. Identify the parts A, B, C and D in the given figure. (Apr 2025)
4. Name the parts of the hind brain (PTA-2)
5. Define reflex arc. (PTA-4)
6. Differentiate Between Voluntary and Involuntary actions (PTA-4)
7. Differentiate Between Medullated and Non-medullated nerve fibre. (PTA-3)
8. Write the functions of cerebellum. (PTA-6)
9. Name the three types of neurons and find its location. (Sep'2020)

3 MARK QUESTIONS

1. With a neat labelled diagram, explain the structure of a neuron. (Apr 2025)
2. Explain how neurons are classified based on its structure. (Jul'2023)
3. Illustrate the structure and functions of brain. (PTA-1)
4. Describe the types of neuron on the basis of their functions. (PTA-3)

UNIT 16: PLANT AND ANIMAL HORMONES

2 MARK QUESTIONS

1. What are Chemical Messengers? (Jul'2025)
2. What is colostrum? How is milk production hormonally regulated? (Apr 2024)
3. What is metastasis? (Apr 2024)
4. What is meant by plant Hormones?
5. What are types of plant Hormones?
6. What are Synthetic Auxins? Give examples. (May'2022)
7. How Auxins are classified.
8. State Endocrinology.
9. What are the endocrine glands?
10. Which gland is called as the 'master gland'? Give reason. (QY-2019)
11. What are the hormones secreted by anterior pituitary gland? (PTA-2)
12. Functions of Insulin.
13. Identify the parts A,B,C and D in the given diagram. (Sep'2020)
14. Functions of Glucocorticoids.
15. Functions of Testosterone.
16. Functions of Thymosin.
17. Functions of Progesterone.
18. What is bolting? How can it be induced artificially? (GMQP-2019)
19. What is parthenocarpic fruit? Give an example. (PTA-6)

3 MARK QUESTIONS

1. Explain physiological effects of Auxins.
2. Explain physiological effects of Cytokinins.
3. Name the gaseous plant hormone. Mention any three of its physiological effects in plants. (Sep'2021)
4. Explain physiological effects of Ethylene. (PTA-3)
5. Explain the functions of thyroid hormones.
6. Why are thyroid hormones referred as personality hormones? (Aug 2022)
7. What are the hormones secreted by posterior lobe of the pituitary gland? Mention the tissues on which they exert their effect. (PTA-2)
8. Identify the disorder with which the person shown in the figure is suffering. (PTA-1)
9. How is Corpus luteum formed? Name the hormones secreted by corpus luteum. (PTA-2)

UNIT 17: REPRODUCTION IN PLANTS AND ANIMALS

2 MARK QUESTIONS

1. Define Triple Fusion. (Jul'2023)
2. What are Okazaki fragments? (Jun 2024)
3. Write note on androecium.
4. Write note on Gynoccium.
5. What is meant by micropyle.
6. What is Bolting? How can it be induced artificially? (Apr 2025)
7. What is pollination. (Sep'2021)
8. Write note on self-pollination.
9. What is meant by cross pollination?
10. Draw the structure of pollen grains and label the parts (Sep'2020)
11. Draw and label the parts of a sperm. (Sep'2021)
12. Draw the structure of Ovum.
13. Name the secondary sex organs in male. (May'2022)
14. Write a note on UTI. (Sep'2020)
15. What is Vegetative propagation practice for growing some type of plants? (PTA-1)
16. How can menstrual hygiene be maintained during menstrual days? (PTA-4)
17. Why is vegetative propagation practiced for growing some type of plants? (PTA-1)

3 MARK QUESTIONS

1. Write the events involved in the Sexual reproduction of a flowering plant. (a) State the types of first event. (b) Mention the advantages and the disadvantages of that event. (Jul'2023)
2. State the importance of pollination. (Sep'2021)
3. Advantages of self-pollination.
4. Disadvantages of self-pollination.
5. Advantages of cross-pollination.
6. Disadvantages of cross-pollination.
7. Explain the process of Fertilization in plants.
8. How does developing embryo gets its nourishment inside the mother's body? (PTA-6)
9. Explain menstrual cycle - process of ovulation. (PTA-3)
10. Explain personal Hygiene, Body Hygiene, toilet hygiene, Menstrual and Napkin Hygiene.
11. Write the Characteristics of insect pollinated flowers. (PTA-6)
12. What is colostrum? How is milk production hormonally regulated? (PTA-2)
13. Identify the parts A, B, C and D. (Aug 2022)
14. What are the phases of menstrual cycle? Indicate the changes In the ovary and uterus. (PTA-3)

5 MARK QUESTIONS

1. (a) (i) Write the events involved in the sexual reproduction of flowering plants. (ii) Discuss the first event and write the types. (iii) Mention the advantages and disadvantages of that event. OR (b) (i) What are the agents of soil erosion? (ii) What are the effects of hybrid vigour in animals? (iii) Name the types of stem cells. (Jun'2024)

UNIT 18: GENETICS

2 MARK QUESTIONS

1. Define genetic engineering. (Apr'2023)
2. Why is Archaeopteryx considered to be a connecting link? (Jul'2023)
3. Define genetics.
4. What do you understand by the term phenotype and genotype? (Aug'2022)
5. What are allosomes? (QY-2019)
6. Define Chromosomes & explain structure of chromosome. (Sep'2021)
7. Define diploid, haploid.
8. What is meant by DNA Replication.
9. What are Okazaki fragments? (PTA-4)
10. Differentiate Phenotype and genotype. (PTA-4)

3 MARK QUESTIONS

1. (a) What do you understand by the term phenotype and genotype? (b) What are allosomes? (Apr'2023)
2. (i) State the applications of DNA fingerprinting technique. (ii) Why is Archaeopteryx considered to be a connecting link? (Jun 2024)
3. State the applications of DNA Finger Printing Techniques. (Jul'2023)
4. (a) What are the consequences of deforestation? (b) State the applications of DNA finger printing technique. (Apr 2024)
5. Write the importance of biotechnology in the field of medicine. (Jul'2023)
6. Why did mendel select pea plant for his experiments? (May'2022)
7. Monohybrid cross-Inheritance of one gene.
8. Dihybrid Cross- Inheritance of two genes and Law of Independent Assortment.
9. Explain Mendel's laws.
10. A pure tall plant (TT) is crossed with pure dwarf plant (tt), what would be the F1 and F2 generations? Explain. (PTA-5)
11. Explain structure of DNA. (QY-2019)
12. Explain Watson and Crick model of DNA.
13. State the application of DNA Fingerprinting technique. (Sep'2020)
14. Write note on Significance of DNA. (Sep'2020)
15. Explain Sex Determination in Human.
16. Pure-bred tall pea plants are first crossed with pure-bred dwarf pea plants. The pea plants obtained in F1 generation are then selfed to produce F2 generation of pea plants. a) What do the plants of F1 generation look like? b) What is the ratio of tall plants to dwarf plants in F2 generation? c) Which type of plants were missing in F1 generation but reappeared in F2 generation. (GMQP-2019)
17. If we cross two different parents with the genotype of $Tt\times tt$, what would be the genotype ratio in its F1 generation? (PTA-3)

5 MARK QUESTIONS

1. (a) How is the structure of DNA organised? What is the biological significance of DNA? OR (b) (i) State the various routes by which transmission of human immunodeficiency virus (HIV) takes place. (ii) State the importance of rainwater harvesting. (Jul'2023)

UNIT 19: ORIGIN AND EVOLUTION OF LIFE

2 MARK QUESTIONS

1. The degenerated wing of a Kiwi is an acquired character. Why is it called an acquired character? (Apr'2025)
2. How can you determine the age of the fossils? (Jul'2025)
3. What is Evolution. (Sep'2021)
4. The degenerated wing of a kiwi is an acquired character. Why is it an acquired character? (PTA-3)
5. How does fossilization occur in plants? (PTA-1)

3 MARK QUESTIONS

1. Define Ethnobotany and write its importance. (Jun'2024)
2. Explain Theories on origin of life.
3. Explain Use and Disuse theory (or) Lamarckism.
4. Explain Darwinism or Theory of natural selection.
5. Define, aspects, Importance Ethnobotany. (Aug 2022)
6. Natural selection is a driving force for evolution - How? (PTA-6)
7. Arun was playing In the garden. Suddenly he saw a dragon fly sitting on a plant. He observed the wings of it. He thought it looked similar to a wing of a crow. Is he correct? Give reason for your answer. (PTA-2)
8. Octopus, cockroach and frog all have eyes. Can we group these animals together to establish a common evolutionary origin. Justify your answer. (PTA-4)

5 MARK QUESTIONS

1. (a) (i) Which hormone induces parthenocarpy in tomatoes? (ii) Why is thyroid hormone referred as 'personality hormone'? (iii) Explain Lamarck's theories of evolution. OR (b) (i) Which enzyme cuts DNA at specific sites? (ii) Name two maize hybrids rich in amino-acid, lysine. (iii) Explain smoking hazards and the harmful effects of tobacco. (Apr 2023)

UNIT 20: BREEDING AND BIOTECHNOLOGY

5 MARK QUESTIONS

1. (a) (ii) Discuss the importance of biotechnology in the field of Medicine. (Jul'2025)
2. Write note on Green Revolution.
3. Explain Methods of Plant Breeding for Crop Improvement.
4. Write note on Animal Breeding, Inbreeding, out breeding.
5. Write note on Heterosis.
6. Explain Biotechnology in Medicine. (Sep'2021)
7. Explain Gene Therapy. (Sep'2020)
8. Name the types of stem cells. (PTA-2)
9. What are transgenic organisms? (PTA-6)
10. Discuss the method of breeding for disease resistance. (PTA-6)
11. Name three improved characteristics of wheat that helped India to achieve high productivity. (PTA-4)
12. Name two maize hybrids rich in amino acid lysine. (May'2022)
13. Distinguish between somatic gene therapy and germ line gene therapy. (Sep 2021)
14. State the applications of DNA finger printing technique. (Sep'2020)
15. What are the effects of hybrid vigour in animals? (PTA-5)
16. Discuss the importance of biotechnology in the field of medicine. (May'2022)
17. Explain about Gene Therapy. (Sep'2020)

UNIT 21: HEALTH AND DISEASES

2 MARK QUESTIONS

1. What are psychotropic drugs? (PTA-2)
2. What are the contributing factors for obesity? (Aug 2022)
3. What are the various routes by which transmission of human immuno deficiency virus takes place? (PTA-1)
4. Differentiate between Type 1 and Type 2 diabetes mellitus. (PTA-4)
5. What precautions can be taken for preventing heart diseases? (Sep'2020)
6. Suggest measures to overcome the problems of an alcoholic. (May'2022)
7. What are the role of fat in the cause of atherosclerosis? (PTA-3)
8. Regular physical exercise is advisable for normal functioning of human body. What are the advantages of practicing exercise in daily life? (PTA-6)
9. How can informational efforts change people's HIV knowledge and behaviour? (PTA-5)
10. Mention any two approaches for protection of an Abused child. (Sep'2020)

4 MARK QUESTIONS

1. Child Abuse, Sexual Abuse, Child Sexual Abuse.
2. Explain Approaches for protection of an abused child. (Sep'2020)
3. Write note on Drug De-addiction.
4. Explain Smoking Hazards and effects of Tobacco.
5. Explain Harmful effects of alcohol to health.
6. Suggest measures to overcome the problems of an alcoholics. (Sep'2021)
7. Explain Obesity, Prevention and control of obesity. (Sep'2021)
8. Explain Preventive measures for cancer.
9. How is cancer cell different from normal cell? (Sep 2021)
10. Explain Symptoms and treatment of AIDS.
11. Explain Prevention and control of AIDS.

UNIT 22: ENVIRONMENTAL MANAGEMENT

2 MARK QUESTIONS

1. What will happen if trees are cut down? (Apr 2025)
2. Enumerate the importance of forests. (Jul'2025)
3. Write note on Nonrenewable energy sources, renewable energy sources.
4. Explain shale gas.
5. Explain water energy.
6. Explain Tidal energy.
7. Explain Rainwater Harvesting.
8. Explain Electrical energy.
9. E-wastes and its management.
10. Why fossil fuels are to be conserved? (Aug 2022)
11. What are the advantages of using biogas? (PTA-1)
12. What is 4R approach. (PTA-1)

3 MARK QUESTIONS

1. (i) What are the consequences of soil erosion? (ii) How will you prevent soil erosion? (Apr'2025)
2. How do rainwater harvesting structures recharge groundwater? (Apr 2023)
3. What are the agents of soil erosion? (PTA-2)
4. How are e-wastes generated? (Sep 2021)
5. What is the importance of rainwater harvesting? (May'2022)
6. How will you prevent soil erosion? (PTA-3)
7. List out the advantages of tidal energy. (PTA-5)

UNIT 23: VISUAL COMMUNICATION

2 MARK QUESTIONS

1. What is stage? (Apr 2024)
2. What is Scratch? (Jun 2024)
3. What is Sprite? (Apr 2023)

3 MARK QUESTIONS

1. Write a note on EDITOR and its main parts. (Jul'2023)

Origin and Evolution of Life: Class 10 Science Book Back Answers

Origin and Evolution of Life

10th Science : Chapter 19 : Book Back Questions with Answers

I. Choose the correct answer

1. Biogenetic law states that ______________
   • a) Ontogeny and phylogeny go together
   • b) Ontogeny recapitulates phylogeny
   • c) Phylogeny recapitulates ontogeny
   • d) There is no relationship between phylogeny and ontogeny
2. The ‘use and disuse theory’ was proposed by ______________.
   • a) Charles Darwin
   • b) Ernst Haeckel
   • c) Jean Baptiste Lamarck
   • d) Gregor Mendel
3. Paleontologists deal with
   • a) Embryological evidences
   • b) Fossil evidences
   • c) Vestigial organ evidences
   • d) All the above
4. The best way of direct dating fossils of recent origin is by
   • a) Radio-carbon method
   • b) Uranium lead method
   • c) Potassium-argon method
   • d) Both (a) and (c)
5. The term Ethnobotany was coined by
   • a) Khorana
   • b) J.W. Harsbberger
   • c) Ronald Ross
   • d) Hugo de Vries

II. Fill in the blanks

1. The characters developed by the animals during their life time, in response to the environmental changes are called adaptation.
2. The degenerated and non-functional organs found in an organism are called vestigial organs.
3. The forelimbs of bat and human are examples of homologous organs.
4. The theory of natural selection for evolution was proposed by Charles Darwin.

III. State true or false. Correct the false statements

1. The use and disuse theory of organs’ was postulated by Charles Darwin. - False

   Correct Statement: The Use and Disuse theory of organs was postulated by Lamarck.

2. The homologous organs look similar and perform similar functions but they have different origin and developmental pattern. - False

   Correct Statement: The homologous organs look dissimilar and perform different functions but they have similar origin and developmental pattern.

3. Birds have evolved from reptiles. - True

IV. Match the following

Exercise: Match the Items

Column A

1. Atavism
2. Vestigial organs
3. Analogous organs
4. Homologous organs
5. Wood park
6. W.F. Libby

Column B

• caudal vertebrae and vermiform appendix
• a forelimb of a cat and a bat’s wing
• rudimentary tail and thick hair on the body
• a wing of a bat and a wing of an insect
• radiocarbon dating
• Thiruvakkarai

Solution

• a) Atavism - rudimentary tail and thick hair on the body
• b) Vestigial organs - caudal vertebrae and vermiform appendix
• c) Analogous organs - a wing of a bat and a wing of an insect
• d) Homologous organs - a forelimb of a cat and a bat’s wing
• e) Wood park - Thiruvakkarai
• f) W. F. Libby - radiocarbon dating

V. Answer in a word or sentence

1. A human hand, a front leg of a cat, a front flipper of a whale and a bat’s wing look dissimilar and adapted for different functions. What is the name given to these organs?

Homologous organs.

2. Which organism is considered to be the fossil bird?

Archaeopteryx.

3. What is the study of fossils called?

Palaeontology.

VI. Short answers questions

1. The degenerated wing of a kiwi is an acquired character. Why is it an acquired character?

(i) When there is a change in the environment, the animals respond to the change.

(ii) They develop adaptive structures. The characters developed by the animals during their life time, in response to the environmental changes are called acquired characters.

(iii) Lamarck’s use and disuse theory states that if an organ is used constantly, the organ develops well and gets strengthened. When an organ is not used for a long time, it gradually degenerates.

Degenerated wing of kiwi is an example for organ of disuse.

Degeneration of wings in kiwi is due to disuse of wings over generations since they have learns to walk on land for all their needs. This is an acquired character in response to their habitat. According to Lamarck such characters are passed to the off springs by inheritance.

2. Why is Archaeopteryx considered to be a connecting link?

(i) Archaeopteryx is the oldest known fossil bird.

(ii) It is considered to be a connecting link between reptiles and birds. It had wings with feathers, like a bird. It had long tail, clawed digits and conical teeth, like a reptile.

3. Define Ethnobotany and write its importance.

(i) Ethnobotany is the study of a region’s plants and their practical uses through the traditional knowledge of the local culture of people.

(ii) The term Ethnobotany was coined by J. W. Harshberger in 1895 to include the study of plants used by the primitive and aboriginal people.

Importance of Ethnobotany :

• (i) It provides traditional uses of plant.
• (ii) It gives information about certain unknown and known useful plants.
• (iii) The ethnomedicinal data will serve as a useful source of information for the chemists, pharmacologists and practitioners of herbal medicine.
• (iv) Tribal communities utilize ethnomedicinal plant parts like bark, stem, roots, leaves, flower bud, flowers, fruits, seeds, oils, resins, dyes, gum for the treatment of diseases like diarrhoea, fever, headache, diabetes, jaundice, snakebites, leprosy, etc.

4. How can you determine the age of the fossils?

(i) The age of fossils is determined by radioactive elements present in it.

(ii) They may be carbon, uranium, lead or potassium. It is used in paleobotany and anthropology for determining the age of human fossils and manuscripts.

Radioactive carbon (C¹⁴) dating method :

• (i) This method was discovered by W.F. Libby (1956).
• (ii) Carbon consumption of animals and plants stops after death and since then, only the decaying process of C¹⁴ occurs continuously.
• (iii) The time passed since death of a plant or animal can be calculated by measuring the amount of C¹⁴ present in their body.

VII. Long answer questions

1. Natural selection is a driving force for evolution-How?

Evolution is the gradual change occurring in living organisms over a period of time. Formation of new species due to changes in specific characters over several generations as response to natural selection, is called evolution. Principles of Darwinism - Theory of Natural selection proposed by Charles Darwin :

Overproduction :

• (i) Living beings have the ability to reproduce more individuals and form their own progeny. (Multiply in Geometrical manner.)
• (ii) This will increase reproductive potential leading to over production.

Struggle for existence: Due to over production, a geometric ratio of increase in population occurs. This creates an intense competition among the organisms for food and space leading to struggle.

The struggle for existence are of three types:

• (i) Intraspecific struggle: Competition among the individuals of same species.
• (ii) Interspecific struggle: Competition between the organisms of different species living together.
• (iii) Environmental struggle: Natural conditions like extreme heat or cold, drought and floods can affect the existence of organisms.

Variations :

• (i) The occurrence of variation is a characteristic feature of all plants and animals. Small variations are important for evolution.
• (ii) According to Darwin favourable variations are useful to the organism and unfavourable variations are harmful or useless to the organism.

Survival of the fittest or Natural selection:

• (i) During the struggle for existence, the organisms which can overcome the challenging situation, survive and adapt to the surrounding environment. Organisms which are unable to face the challenges, are unfit to survive and disappear.
• (ii) The process of selection of organisms with favourable variation is called as natural selection.

Origin of species:

• (i) According to Darwin, new species originates by the gradual accumulation of favourable variations for a number of generations.

Hence natural selection is a driving force for evolution since it leads to formation of new species.

2. How do you differentiate homologous organs from analogous organs?

Homologous organs :

• (i) The homologous organs are those which have inherited from common ancestors with similar developmental pattern in embryos.
• E.g: A human hand, a front leg of a cat, flipper of a whale and a bat’s wing look dissimilar and adapted for different functions.
• (ii) Their mode of development and basic structure of bone are similar.

Analogous organs :

• The analogous organs look similar and perform similar functions but they have different origin and developmental pattern.
• E.g: The function of the wings of a bat, the wings of a bird and wings of an insect are similar but their basic structures are different.

3. How does fossilization occur in plants?

The process of formation of fossil in the rocks is called fossilization.

Common methods of fossilization includes:

• (i) Petrifaction
• (ii) Molds and Cast
• (iii) Carbonization
• (iv) Preservation
• (v) Compression
• (vi) Infiltration.

(i) Petrifaction:

1. Minerals like silica slowly penetrate in and replace the original organic tissue and forms a rock like fossil.
2. This method of fossilization can preserve hard and soft parts. Most bones and wood fossils are petrified.

(ii) Mold and Cast:

1. A replica of a plant or animal is preserved in sedimentary rocks.
2. When the organism gets buried in sediment it is dissolved by underground water leaving a hollow depression called a mold.
3. It shows the original shape but does not reveal the internal structure.
4. Minerals or sediment fill the hollow depression and forms a cast.

(iii) Preservation :

1. Original remains can be preserved in ice or amber (tree sap).
2. They protect the organisms from decay. The entire plant or animal is preserved.

(iv) Compression :

1. When an organism dies, the hard parts of their bodies settle at the bottom of the sea bed and are covered by sediment.
2. The process of sedimentation goes on continuously and fossils are formed.

(v) Infiltration or Replacement:

1. The precipitation of minerals takes place which later on infiltrate the cell wall.
2. The process is brought about by several mineral elements such as silica, calcium carbonate and magnesium carbonate.
3. Hard parts are dissolved and replaced by these minerals.

IX. Higher Order Thinking Skills (HOTS)

1. Arun was playing in the garden. Suddenly he saw a dragon fly sitting on a plant. He observed the wings of it. He thought it looked similar to a wing of a crow. Is he correct? Give reason for your answer.

(i) No. Wings of a dragon fly are different from the wings of crow. In the case of a crow, wings represent modified forelimbs.

(ii) Wings of a dragon fly and crow have the same function. They serve to fly but their origin and developmental pattern are different. Such organs which look similar and perform similar function but have different origin and developmental pattern are called analogous organs.

2. Imprints of fossils tell us about evolution-How?

(i) Fossils are evidence for evolution.

(ii) Fossils are the most important proof for evolution of life on earth over millions of years. They show that life on earth was once different from life found on earth today.

(iii) By Studying fossils, help scientists to gather information about plants and animals which lived in the past ages.

(iv) A plant fossil is any preserved part of a plant that has died long back.

(v) Fossils may be a prehistoric impression that may be hundred to millions of years old.

(vi) Majority of the plant fossils are disarticulated parts of plants, it is rare to find plants to be preserved as whole.

Importance of fossils :

• (i) They throw light on phylogeny and evolution of plants.
• (ii) Fossil plants give a historical approach to plant kingdom.
• (iii) Thus even if fossils are not available as a whole, imprints or separated parts will also be able to give us lot of information about evaluation.

3. Octopus, cockroach and frog all have eyes. Can we group these animals together to establish a common evolutionary origin. Justify your answer.

(i) No. These animals cannot be grouped together. Only the presence of eyes is not a factor to group animals together.

(ii) The interrelationship of the organism must be supported by evidence from other disciplines of biology.

(iii) Octopus and cockroach belong to phylum Arthropoda. (Invertebrates) Frog belongs to phylum Chordata. (Vertebrates).

(iv) Based on the presence of a single character, animals cannot be grouped to establish a common evolutionary origin.

Concept Maps

Reproduction in Plants and Animals: Book Back Questions and Answers | Class 10 Science

Reproduction in Plants and Animals

10th Science | Chapter 17: Book Back Questions with Answers

I. Choose the correct answer

1. The plant which propagates with the help of its leaves is ___________ .

   1. Onion
   2. Neem
   3. Ginger
   4. Bryophyllum

2. Asexual reproduction takes place through budding in ___________ .

   1. Amoeba
   2. Yeast
   3. Plasmodium
   4. Bacteria

3. Syngamy results in the formation of _________ .

   1. Zoospores
   2. Conidia
   3. Zygote
   4. Chlamydospores

4. The essential parts of a flower are ___________ .

   1. Calyx and Corolla
   2. Calyx and Androecium
   3. Corolla and Gynoecium
   4. Androecium and Gynoecium

5. Anemophilous flowers have __________ .

   1. Sessile stigma
   2. Small smooth stigma
   3. Colored flower
   4. Large feathery stigma

6. Male gametes in angiosperms are formed by the division of ___________ .

   1. Generative cell
   2. Vegetative cell
   3. Microspore mother cell
   4. Microspore

7. What is true of gametes?

   1. They are diploid
   2. They give rise to gonads
   3. They produce hormones
   4. They are formed from gonads

8. A single highly coiled tube where sperms are stored, get concentrated and mature is known as

   1. Epididymis
   2. Vasa efferentia
   3. Vas deferens
   4. Seminiferous tubules

9. The large elongated cells that provide nutrition to developing sperms are

   1. Primary germ cells
   2. Sertoli cells
   3. Leydig cells
   4. Spermatogonia

10. Estrogen is secreted by

    1. Anterior pituitary
    2. Primary follicle
    3. Graffian follicle
    4. Corpus luteum

11. Which one of the following is an IUCD?

    1. Copper – T
    2. Oral pills
    3. Diaphragm
    4. Tubectomy

II. Fill in the blanks

1. The embryo sac in a typical dicot at the time of fertilization is 7 celled.
2. After fertilization the ovary develops into fruit.
3. Planaria reproduces asexually by Regeneration.
4. Fertilization is Internal in humans.
5. The implantation of the embryo occurs at about 7th day of fertilization.
6. Colostrum is the first secretion from the mammary gland after child birth.
7. Prolactin is a hormone produced by pituitary gland.

III (a) Match the following

Answer

Fission : Amoeba

Budding : Yeast

Fragmentation : Spirogyra

(b) Match the following terms with their respective meanings

a) Parturition

b) Gestation

c) Ovulation

d) Implantation

1) Duration between pregnancy and birth

2) Attachment of zygote to endometrium

3) Delivery of baby from uterus

4) Release of egg from Graafian follicle

Answer

a) Parturition - Delivery of baby from uterus

b) Gestation - Duration between pregnancy and birth

c) Ovulation - Release of egg from Graafian follicle

d) Implantation - Attachment of zygote to endometrium

IV. State whether the following statements are True or False. Correct the false statement

1. Stalk of the ovule is called pedicle. - False

   Stalk of the ovule is called funicle.

2. Seeds are the product of asexual reproduction. - False

   Seeds are the product of sexual reproduction.

3. Yeast reproduces asexually by means of multiple fission. - False

   Yeast reproduces asexually by budding.

4. The part of the pistil which serves as a receptive structure for the pollen is called as style. - False

   The part of the pistil which serves as a receptive structure for the pollen is called stigma.

5. Insect pollinated flowers are characterized by dry and smooth pollen. - False

   Wind pollinated flowers are characterized by dry and smooth pollens, (or) Insect pollinated flowers are characterized by large and spiny pollens.

6. Sex organs produce gametes which are diploid. - False

   Sex organs produce gametes which are haploid.

7. LH is secreted by the posterior pituitary.

8. Menstrual cycle ceases during pregnancy. - True

9. Surgical methods of contraception prevent gamete formation. - False

   Surgical methods of contraception prevent fertilization.

10. The increased level of estrogen and progesterone is responsible for menstruation. - False

    The decrease in level of estrogen and progesterone is responsible for menstruation.

V. Answer in a word or sentence

1. If one pollen grain produces two male gametes, how many pollen grains are needed to fertilize 10 ovules?

   10 pollen grains.

2. In which part of the flower germination of pollen grains takes place?

   Stigma.

3. Name two organisms which reproduces through budding.

   Yeast and Hydra.

4. Mention the function of endosperm.

   Endosperm provides food to the developing embryo.

5. Name the hormone responsible for the vigorous contractions of the uterine muscles.

   Oxytocin.

6. What is the enzyme present in acrosome of sperm?

   Hyaluronidase.

7. When is World Menstrual Hygiene Day observed?

   May 28.

8. What is the need for contraception?

   It is a birth control measure.

9. Name the part of the human female reproductive system where the following occurs.

   a. Fertilization b. Implantation

   (a) Fertilization - Fallopian tube

   (b) Implantation - Uterus.

VI. Short answer question

1. What will happen if you cut planaria into small fragments?

   (i) Planaria can be cut into any number of pieces and each piece gives rise to a complete organism.

   (ii) The ability, of the lost body parts of an individual organism to give rise to a whole new organism is called regeneration. It takes place by specialized mass of cells e.g Hydra and Planaria.

2. Why is vegetative propagation practiced for growing some type of plants?

   (i) Some plants do not produce seeds. Hence vegetative propagation is practiced to propagate such plants.

   (ii) Further vegetative propagation will help to retain the parental characters in the next generation as required for some high yielding varieties.

3. How does binary fission differ from multiple fission?

   In binary fission only two daughter cells are produced whereas in multiple fission many daughter cells are produced.

   Eg: Amoeba (Binary fission)

   Plasmodium (Multiple fission)

4. Define triple fusion.

   (i) During fertilization process in Angiosperms, the pollen grain produces two sperms.

   (ii) One sperm, fuses with the egg and forms a diploid zygote.

   (iii) Another sperm fuses with the secondary nucleus (2n) of the embryo sac and forms a triploid primary endosperm nucleus. This is called triple fusion.

5. Write the characteristics of insect pollinated flowers.

   (i) Pollination with the help of insects like honeybees, flies is called entomophily.

   (ii) To attract insects these flowers are brightly coloured, have smell, and nectar.

   (iii) The pollen grains are larger in size, the exine is pitted, spiny etc. So that they can adhere to the stigma.

6. Name the secondary sex organs in male

   The secondary sex organs in male include the vas deferens, epididymis, seminal vesicle, prostate gland and penis.

7. What is colostrum? How is milk production hormonally regulated?

   (i) The first fluid which is released from the mammary gland after child birth is called as colostrum.

   (ii) Milk production from alveoli of mammary glands is stimulated by prolactin secreted from the anterior pituitary.

   (iii) The ejection of milk is stimulated by posterior pituitary hormone oxytocin.

8. How can menstrual hygiene be maintained during menstrual days?

   (i) Sanitary pads should be changed regularly, to avoid infections due to microbes from vagina and sweat from genitals.

   (ii) Use of warm water to clean genitals helps to get rid of menstrual cramps.

   (iii) Wearing loose clothing rather than tight- fitting clothes will ensure the airflow around the genitals and prevent sweating.

9. How does developing embryo gets its nourishment inside the mother's body?

   (i) The placenta is a disc shaped structure attached to the uterine wall and is a temporary association between the developing embryo and maternal tissues.

   (ii) It allows the exchange of food materials, diffusion of oxygen, excretion of nitrogenous wastes and elimination of carbon dioxide.

   (iii) A cord containing blood vessels that connects the placenta with the foetus is called the umbilical cord.

10. Identify the parts A, B, C and D

    

    A - Exine

    B - Intine

    C - Generative cell

    D - Vegetative nucleus

11. Write the events involved in the sexual reproduction of a flowering plant.

    a. Discuss the first event and write the types.

    b. Mention the advantages and the disadvantages of that event.

    (a) Process of sexual reproduction in flowering plants involves :

    1. Pollination
    2. Fertilization

    Pollination : The transfer of pollen grains from anther to stigma of a flower is called as pollination.

    Types of pollination :

    1. Self-pollination
    2. Cross pollination

    Self-pollination (Autogamy) : Self- pollination is also known as autogamy. The transfer of pollen grain from the anther to the stigma of same flower or another flower borne on the same plant is known as self- pollination. e.g. Hibiscus.

    (b) Advantages of self-pollination:

    • (i) Self-pollination is possible in certain bisexual flowers.
    • (ii) Flowers do not depend on agents for pollination.
    • (iii) There are no wastages of pollen grains.

    Disadvantages of self-pollination:

    • (i) The seeds are less in number.
    • (ii) The endosperm is minute. Therefore, the seeds produce weak plants.
    • (iii) New varieties of plants cannot be produced Cross pollination.

    Cross-pollination is the transfer of pollen from the anthers of a flower to the stigma of a flower on another plant of the same species, e.g. apples, grapes, plum, etc.

    Advantages of cross pollination:

    • (i) The seeds produced as a result of cross pollination, develop and germinate properly and grow into better plants, i.e., cross pollination leads to the production of new varieties.
    • (ii) More viable seeds are produced.

    Disadvantages of cross-pollination:

    • (i) Pollination may fail due to distance barrier.
    • (ii) More wastage of pollen grains.
    • (iii) It may introduce some unwanted characters.
    • (iv) Flowers depend on the external agencies for pollination.

12. Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present.

    (i) The testes are present inside a pouch called scrotal sac.

    (ii) The testes are located outside the abdominal cavity because sperms develop at a temperature, several degrees cooler than normal internal body temperature.

13. Luteal phase of the menstrual cycle is also called the secretory phase. Give reason.

    (i) During the luteal phase, the hormone progesterone is secreted by the corpus luteum, which develops from the ruptured graffian follicles.

    (ii) Its level increases. If menstrual bleeding occurs, the level will decrease.

    (iii) Hence the luteal phase of menstrual cycle is also called secretory phase.

14. Why are family planning methods not adopted by all the people of our country?

    (i) Family planning is a way of living that is adopted voluntarily by couples on the basis of knowledge and responsible decisions to promote the health and welfare of the family group and society.

    (ii) The WHO (World Health Organisation) has also stressed the importance of family planning as global health strategy for all.

    (iii) Further many families especially in the lower strata of society believe that many children in a family can contribute to more income and do not adopt family planning.

VII. Long answer questions

1. With a neat labelled diagram describe the parts of a typical angiospermic ovule.

   Answer:

   (i) The main part of the ovule is the nucellus which is enclosed by two integuments leaving an opening called as micropyle.

   

   (ii) The ovule is attached to the ovary wall by a stalk known as funiculus. Chalaza is the basal part.

   (iii) The embryo sac contains seven cells and eight nuclei located within the nucellus.

   (iv) Three cells at the micropylar end form the egg apparatus and the three cells at the chalaza end are the antipodal cells.

   (v) The remaining two nuclei are called polar nuclei found in the centre. In the egg apparatus one is the egg cell (female gamete) and the remaining two cells are the synergids.

2. What are the phases of menstrual cycle? Indicate the changes in the ovary and uterus.

   Answer:

   Events of menstrual cycle and the role of hormones.

   

VIII. Higher Order Thinking Skills (HOTS)

1. In angiosperms the pollen germinates to produce pollen tube that carries two gametes. What is the purpose of carrying two gametes when single gamete can fertilize the egg?

   (i) The second gamete fuses with diploid secondary nucleus in the embryo sac of the ovule.

   (ii) This forms the triploid endosperm nucleus which develops into the endosperm tissue and gives nourishment to the developing embryo.

   (iii) When the ovule forms the seed after fertilization the endosperm serves to give nourishment to the embryo during germination until the first set of foliage leaves are formed by the seedling or baby plant.

2. Why menstrual cycle does not take place before puberty and during pregnancy?

   (i) The menstrual cycle begins only after the complete development of the gonads. During puberty, the gonads become functional and hence menstrual cycle begins.

   (ii) Pregnancy is initiated by fertilization and zygote formation. The zygote gets implanted in the uterus. The ruptured follice develops into a temporary endocrine gland called corpus luteum to produce hormones. Uterine wall is thickened to receive the zygote.

   If fertilization does not take place, corpus luteum degenerates, uterine wall ruptures and unfertilized egg is expelled resulting in menstruation. Hence menstrual cycle does not occur during pregnancy.

3. Read the following passage and answer the questions that follow

   Rahini and her parents were watching a television programme. An advertisement flashed on the screen which was promoting use of sanitary napkins. Rahini’s parents suddenly changed the channel, but she objected to her parents and explained the need and importance of such advertisement.

   a) What is first menstruation called? When does it occur ?

   b) List out the napkin hygiene measures taken during menstruation ?

   c) Do you think that Rahini’s objection towards her parents was correct? If so, Why?

   (a) Menarche : It occurs at the age of 11 - 13 years.

   (b) Napkin hygiene: The parents and teachers are to create awareness among the school girls about the use of napkins and their proper disposal. Girls should be educated in the following ways :

   • i. The sanitary pad and tampons should be wrapped properly and discarded because they can spread infections.
   • ii. Sanitary pad or tampon should not be flushed down the toilet.
   • iii. Napkin incinerators are to be used properly for disposal of used napkins.

   (c) Yes, her objection was right. The advertisements create awareness. Thus by watching such advertisements girls and their parents will gain knowledge about such products and their usage.

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