How do Organisms Reproduce Important Questions Class 10 2026

The chapter How Do Organisms Reproduce is one of the most conceptually important and high-weightage topics in Class 10 Biology. It also helps students understand both simple and complex forms of reproduction, from single-celled organisms to higher animals, including humans.

By studying this chapter, you learn about asexual and sexual reproduction, the structure and function of reproductive organs, and the processes involved in human reproduction. The topic also builds your foundation for advanced studies in genetics and evolution in higher classes.

This chapter’s Important Questions for Class 10 Biology are curated to help you:

• Strengthen your conceptual understanding of reproductive mechanisms.
• Practice diagram-based and reasoning questions commonly asked in CBSE exams.
• Prepare efficiently for both school tests and board examinations.

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Chapter 7 How Do Organisms Reproduce Important Questions

Q1. Planarians can regenerate lost body parts due to the presence of specialised cells called neoblasts. These specialised cells multiply and make a large mass of cells from which different cells undergo changes to become different types of cells and tissues.

(a) In plants, in which type of tissue are cells that have a function similar to neoblasts found?

(b) How do the characteristics of a planarium formed by regeneration compare with the characteristics of the original planarium? Justify your answer.

Answer: Here are the answers of the following:

(a) In plants, the tissue containing cells with a function similar to neoblasts is the meristematic tissue.

Meristematic tissues consist of undifferentiated, actively dividing cells that can develop into various types of cells and tissues, similar to how neoblasts function in planarians. Examples include the apical meristem, lateral meristem, and intercalary meristem, which contribute to growth and repair in plants.

(b) The characteristics of a planarian formed by regeneration are identical to the original planarian.

Justification: Regeneration in planarians relies on the neoblasts, which are totipotent stem cells. These cells contain the complete genetic information required to recreate all the tissues and structures of the original organism. Thus, the regenerated planarian has the same structural and functional characteristics as the original one, provided the regeneration process is complete and accurate.

Q2. What could be the TWO most likely reasons for unicellular organisms to reproduce only through asexual reproduction?

Answer: The two most likely reasons for unicellular organisms to reproduce only through asexual reproduction are:

1. Simplicity and Efficiency

Asexual reproduction, such as binary fission, is a straightforward and rapid process. It requires only one parent and involves simple cell division, allowing unicellular organisms to reproduce quickly and efficiently without the need for complex structures or processes. This efficiency is crucial for survival in environments with abundant resources or where rapid population growth is advantageous.

2. Genetic Stability

Unicellular organisms often rely on asexual reproduction to maintain genetic consistency across generations. This ensures that well-adapted traits suited to their environment are preserved without the potential disruptions caused by genetic recombination in sexual reproduction.

These factors enable unicellular organisms to thrive in diverse and often rapidly changing environments.

Q3. A farmer bought some strawberries and liked the taste. He decided to grow his own strawberries that should have the same taste.

(a) Which method of cultivation should the farmer adopt?

(b) Why would the farmer choose this method?

Answer:

(a) The farmer should adopt vegetative propagation (specifically, using runners or stolons).

• Runners are horizontal stems that grow from the parent strawberry plant. These runners develop into new plants, ensuring that the offspring are genetically identical to the parent plant.

(b) The farmer would choose this method because:

• Cloning of desirable traits: By using vegetative propagation, the farmer ensures that the new plants are genetically identical to the parent plant, which means they will have the same taste and other desirable characteristics.
• Consistency in quality: Since the farmer liked the taste of the strawberries, using runners guarantees that the taste will remain consistent across all the new plants, as they are clones of the original plant.

Q4. Plants produced through vegetative propagation are genetically identical to their parents.

What could be the biggest disadvantage of vegetative propagation?

Answer: The biggest disadvantage of vegetative propagation is the lack of genetic diversity.

Since plants produced through vegetative propagation are genetically identical to their parents, they are clones. This means they do not have the genetic variation needed to adapt to changing environmental conditions, such as new pests, diseases, or shifts in climate. If one plant is susceptible to a disease or adverse condition, all the plants produced through vegetative propagation will likely share the same vulnerability, potentially leading to a higher risk of crop failure or population decline.

Q5. 'In vitro fertilisation' is a process of fusing a human egg and sperm outside a woman's body, in a laboratory. After fertilisation, the zygote is allowed to develop into an embryo for 2-6 days. The embryo is then implanted in the woman's uterus, where it develops normally.

Which labelled region in the diagram BEST represents reproduction via in vitro fertilisation?

Answer: In the process of in vitro fertilization (IVF), fertilization occurs outside the body in a laboratory setting, but implantation happens inside the body in the woman's uterus.

Based on this description, the best labelled region in the diagram to represent reproduction via in vitro fertilization would be the region that indicates fertilization outside the body (such as the laboratory setting where the sperm and egg meet), and then the region showing implantation in the uterus where the embryo is placed for further development.

In diagrams illustrating the human reproductive system or fertilization processes, this would correspond to:

• Fertilization happening in a lab or external environment (outside the woman's body).
• Implantation in the uterus after embryo development.

So, the labelled region representing the fertilization outside the body and subsequent implantation would be the most accurate representation of in vitro fertilization.

Q6. Bindu wants to produce a hybrid variety of tomatoes. She has tomato plants X and Y belonging to two different varieties, one with smooth, long fruits and the other one with wrinkled, round fruits.

Tomatoes have bisexual flowers. Bindu carries out the following steps carefully to cross pollinate the flowers of plants X and Y:

a. She removes a part of the flowers of tomato plant X just before the flowers bloom.

b. She manually pollinates the flowers of tomato plant X using pollen from the flowers of tomato plant Y.

c. She ties small plastic bags around the pollinated flowers of tomato plant X. The plastic bags are removed after a couple of days.

Bindu carried out step 1 so as to prevent self-pollination. Which part did she remove?

Answer: To prevent self-pollination in the tomato flowers of plant X, Bindu likely removed the anthers from the flowers of tomato plant X in step 1.

Explanation:

• The anthers are the male reproductive parts of a flower that produce pollen. By removing the anthers, Bindu ensured that plant X could not self-pollinate because it would not have its own pollen available for fertilization.
• This step is crucial in cross-pollination because it forces Bindu to manually pollinate the flowers using pollen from plant Y, ensuring that the offspring will be a hybrid of the two tomato plants.

By removing the anthers, Bindu effectively prevents self-pollination and ensures that only the pollen from plant Y can fertilize the flowers of plant X, leading to hybrid offspring.

Q7. The description of a species of fish called 'guppy' is given below:

"Guppies are live-bearing fish, with a gestation period of 21-30 days. Once inseminated, female guppies can store sperm in their ovaries, which can continue to fertilize ova up to eight months, meaning the female mate can give birth to the male's offspring long after the male's death."

(a) Based on the given information, which labelled regions CAN guppies belong to? 

(b) What additional information is required to identify the labelled region in the diagram that guppies ACTUALLY belong to?

Answer:

(a) Based on the given information, guppies can belong to the live-bearing fish region.

• Guppies are described as live-bearing fish (they give birth to live young, not lay eggs), which means they fall under a category of fish that reproduce through internal fertilization and give birth to fully developed young.

(b) The additional information required to identify the labelled region in the diagram where guppies actually belong would include:

• Taxonomic classification: To identify the exact region in a diagram, we would need to know the family, order, or class of the guppy. Guppies belong to the family Poeciliidae and the order Cyprinodontiformes.
• Reproductive mode: Although guppies are live-bearing, this characteristic alone might not fully specify the region of classification. We would need to check if the region being considered distinguishes between live-bearing species and egg-laying species, or if it includes specific reproductive characteristics like sperm storage and extended fertilization periods.

Therefore, additional information about the specific classification (family or order) and reproductive features would help pinpoint the exact region where guppies belong in the diagram.

Q8. Two statements are given - one labelled Assertion (A) and the other labelled Reason (R). Read the statements carefully and choose the option that correctly describes statements A and R.

Assertion (A): Oral contraceptive pills and copper-T do not prevent sexually transmitted diseases.Reason (R): Sexually transmitted disease are transmitted by contact with mucous membranes of infected organs.

a. Both A and R are true and R is the correct explanation of A.

b. Both A and R are true but R is not the correct explanation of A.

c. A is true but R is false.

d. A is false but R is true.

Answer:(b) Both A and R are true but R is not the correct explanation of A.

Explanation:

Assertion (A): "Oral contraceptive pills and copper-T do not prevent sexually transmitted diseases."

This statement is true because oral contraceptive pills and copper-T (IUD) are designed to prevent pregnancy, not sexually transmitted diseases (STDs). They do not provide protection against infections like HIV, gonorrhea, or chlamydia, which are transmitted through sexual contact.

Reason (R): "Sexually transmitted diseases are transmitted by contact with mucous membranes of infected organs."

This statement is also true. STDs are primarily transmitted through the exchange of bodily fluids (semen, vaginal fluids, blood, etc.) during sexual contact, which involves the mucous membranes of reproductive organs, and sometimes oral or anal regions.

While both statements are true, the reason provided does not directly explain why oral contraceptives and copper-T do not prevent STDs. These methods work to prevent pregnancy, not infection, so R does not fully explain A.

Q9. The biological sex of an individual only depends on the sperm cell."

Is the above statement true or false? Justify your answer.

Answer: The statement "The biological sex of an individual only depends on the sperm cell" is false. Biological sex determination typically depends on the combination of sex chromosomes inherited from both the egg cell (from the mother) and the sperm cell (from the father).

The egg cell always contributes an X chromosome.

The sperm cell can contribute either an X or a Y chromosome.

• If the sperm carries an X chromosome, the resulting offspring will be female (XX).
• If the sperm carries a Y chromosome, the resulting offspring will be male (XY).

Thus, the biological sex of an individual is determined by both the egg cell and the sperm cell, but the sperm cell plays a key role in determining whether the individual is male or female, depending on whether it carries an X or Y chromosome. Therefore, the statement is inaccurate since it only attributes sex determination to the sperm cell, ignoring the contribution of the egg.

Q10. In the diagram below, each labelled region (P to W) represents a certain combination of reproductive processes found in an animal. Each labelled region is characterised by the different circles that it is (or is not) a part of.

Answer the following questions based on this diagram.

Name any one animal whose mode of reproduction is represented by region P.

Answer: The area labeled P in the diagram refers to internal fertilization.

Internal fertilization is a type of sexual reproduction where the sperm and egg unite inside the female's body. This process occurs in humans.

Some More Important Question Answers

Q1. Why is reproduction important for organisms?

Ans. 

• Every living organism has a limited lifespan, after which it dies.
• If organisms do not reproduce, their species will disappear after one generation.
• Reproduction ensures continuity of species.
• In sexual reproduction, new combinations of genes (variations) arise. Some of these variations are useful in adapting to changing environments.
• Example: Bacteria reproduce rapidly; if one bacterium develops antibiotic resistance (variation), it can survive and pass this trait on.

So, reproduction is not just for producing new organisms, but also for helping species survive through environmental changes.

Q2. Differentiate between asexual and sexual reproduction.

Ans.

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Q3. Explain binary fission in Amoeba.

Ans. Binary fission = division of one organism into two. here are the steps:

1. Parent Amoeba’s nucleus elongates.
2. The nucleus divides into two identical nuclei (mitosis).
3. Cytoplasm divides, each part surrounding a nucleus.
4. Two daughter Amoebas are formed, genetically identical.

Q4. Describe multiple fission in Plasmodium. Why is it advantageous?

Ans. 

• In multiple fission, the nucleus divides repeatedly inside a cyst.
• Each nucleus gets cytoplasm, forming many daughter organisms.
• When cyst bursts → all new individuals are released at once.
• Advantage: Increases chances of survival; if some are destroyed by the host's immunity, others survive.
• Example: Plasmodium (causes malaria). In RBCs, it undergoes multiple fission, releasing many parasites that attack new cells at once, causing fever cycles.

Q5. What is budding? Explain with reference to Hydra.

Ans. 

• Budding: A new organism develops as a small outgrowth (bud) from the parent body.
• In Hydra:
  
  1. A small bud forms due to repeated cell division at one spot.
  2. The bud grows, develops tentacles and mouth.
  3. It detaches from the parent and becomes independent.

example: Hydra with small bud → bud grows → separates → new Hydra.

Q6. Differentiate between fragmentation and regeneration.

Ans. 

• Fragmentation: Body breaks into two or more pieces, and each piece grows into a complete organism. Eg: Spirogyra filament.
• Regeneration: Organism regrows its lost parts. Requires special regenerative cells. Eg: Planaria can regenerate a complete organism from cut pieces.

Note: Not all organisms can regenerate. Higher animals (like humans) only regenerate tissues (skin, liver), not the whole body.

Q7. Define vegetative propagation. Give examples.

Ans. Formation of new plants from vegetative parts of the parent (root, stem, leaf, bud). Here are the examples:

• Stem: Potato tuber (buds or “eyes”).
• Leaf: Bryophyllum leaf develops buds on margins.
• Root: Sweet potato, carrot.

Q8. Write two advantages of vegetative propagation.

Ans. 

1. Produces plants quickly, even without seeds. Eg: banana, sugarcane, rose.
2. All plants are identical to their parents → useful to preserve desirable traits (taste, color, disease resistance).

Q9. Draw and explain the structure of a bisexual flower.

Ans. Main parts of flower:

• Sepals (green): Protect flower bud.
• Petals (colored): Attract pollinators.
• Stamen (male): Anther (makes pollen) + filament.
• Carpel (female): Stigma (receives pollen), Style (tube), Ovary (contains ovules).

Q10. Explain pollination and its types.

Ans. 

• Pollination: Transfer of pollen from another to stigma.
• Self-pollination: Same flower/plant. Eg: pea.
• Cross-pollination: Different plants of the same species. Eg: papaya, maize, Cross-pollination gives more variation.
• Agents: Wind (maize), insects (bees), water (hydrilla), animals (birds, bats).

Q11. Describe double fertilization in flowering plants.

Ans. Unique feature of angiosperms, here are the steps:

1. Pollen grain germinates on stigma → pollen tube grows through style into ovary.
2. Two male gametes released:
   
   • One fuses with egg → zygote (2n).
   • Other fuses with two polar nuclei → endosperm (3n) (food for embryo).

This is called double fertilization as two fusions occur.

Q12. Why do flowers produce nectar?

Ans.

• Nectar is a sugary liquid secreted by flowers.
• Attracts insects like bees, butterflies → they carry pollen from one flower to another (cross-pollination).
• Helps plant reproduction and ensures seed/fruit formation.

Q13. How does sexual reproduction help in evolution?

Ans. 

• Combines genetic material from two parents.
• Introduces variations (new gene combinations).
• Variations increase chances of survival if the environment changes.
• Eg: Some offspring may tolerate drought, others disease → ensures some survive.

Q14. Differentiate unisexual and bisexual flowers with examples.

• Unisexual flower: Has either stamens or carpels, not both. Eg: papaya (male/female separate).
• Bisexual flower: Has both stamens + carpels. Eg: hibiscus, mustard.

Q15. Why are testes located outside the body in humans?

Ans. 

• Sperms require temperature 2–3°C lower than normal body temperature.
• Testes are located in the scrotum (outside abdomen) to maintain this temperature.
• If testes were inside, high body heat would destroy sperms → infertility.

Q16. Describe human female reproductive system.
Ans.
Main parts:

1. Ovaries: Produce eggs + hormones (estrogen, progesterone).
2. Oviducts/Fallopian tubes: Receive egg from ovary; site of fertilization.
3. Uterus: Thick wall; zygote implants and develops here.
4. Cervix + Vagina: Birth canal, receives sperms during intercourse.

Q17. What changes occur in girls during puberty?

Ans. here are the changes occur in girls during puberty 

• Menstrual cycle starts.
• Breasts enlarge.
• Growth of hair in pubic and armpit regions.
• Pelvis widens; fat deposition around hips.
• Emotional + hormonal changes.

Q18. Explain the menstrual cycle in brief.

Ans. Cycle length: 28 days (approx).

1. Day 1–5: Menstruation (bleeding, shedding of uterine lining).
2. Day 6–13: Uterus lining rebuilds, egg matures.
3. Day 14: Ovulation (egg released).
4. Day 15–28: If fertilization occurs → pregnancy; if not → lining breaks, cycle restarts.

Q19. Name any two sexually transmitted diseases (STDs) and prevention.

Ans.  Examples: AIDS (HIV), Syphilis, Gonorrhea.

Here are the Prevention:

• Use of condoms.
• Avoid sharing needles/blades.
• Maintain one faithful partner.
• Regular medical checkups.

Q20. What is contraception? Write natural and artificial methods.

Ans. Contraception: Preventing pregnancy by stopping fertilization or implantation.

Natural methods:

• Abstinence during the fertile period.
• Withdrawal before ejaculation.

Artificial methods:

• Barrier: Condoms, diaphragms.
• Intrauterine devices: Copper-T.
• Oral pills (hormones).
• Surgical: Vasectomy (male), Tubectomy (female).

Video Lecture: Must-watch for Quick Revision

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Extra Questions for Practice!

Q1. Why is variation important for species survival?

Q2. Explain spore formation in Rhizopus with a diagram.

Q3. Why do gametes have half the number of chromosomes?

Q4. Describe fertilization in humans step by step.

Q5. Differentiate between binary fission in Amoeba and multiple fission in Plasmodium.

Q6. Write two advantages and disadvantages of sexual reproduction.

Q7. What is the role of placenta during pregnancy?

Q8. How does cross-pollination occur in maize and papaya?

Q9. Why do humans reproduce sexually and not asexually?

Q10. Define puberty. Mention changes seen in boys.

How to Ace These Class 10 How Do Organisms Reproduce? Important Questions

This chapter involves both theory and diagrams, so conceptual clarity and neat presentation are essential. Follow these steps for effective preparation:

Step 1: Read NCERT Thoroughly

Start by reading the NCERT chapter carefully. Pay special attention to definitions, processes, and examples of reproduction in different organisms.

Step 2: Learn the Types of Reproduction

Understand the difference between asexual and sexual reproduction. Study asexual reproduction methods such as fission, budding, fragmentation, spore formation, and vegetative propagation. Note examples for each method from both plants and microorganisms.

Step 3: Revise Sexual Reproduction in Plants

Study the structure of a flower and its reproductive parts such as stamens, pistils, and ovules. Understand the steps of pollination, fertilization, and seed formation.

Step 4: Understand Human Reproduction

Learn about the male and female reproductive systems, including the main organs and their functions. Study the process of fertilization, zygote formation, embryo development, and childbirth.

Step 5: Study the Role of Hormones and Puberty

Understand how hormones regulate reproductive functions and how puberty leads to reproductive maturity.

Step 6: Practise Diagrams

Draw and label diagrams of the flower, male reproductive system, and female reproductive system. These are frequently asked in exams and carry marks for accuracy and labeling.

Step 7: Revise Reproductive Health and Contraception

Learn about methods of contraception, their importance, and how they help maintain reproductive health and population control.

Step 8: Solve Case-Based and Assertion Questions

Go through sample papers and practice application-based questions related to processes like fertilization, pollination, or vegetative propagation.

Benefits of Practising These Class 10 How Do Organisms Reproduce? 

Here are the benefits of practising these class 10 how do organisims reproduce chapter:

• Complete Concept Coverage: Includes both plant and human reproductive processes in a simple and clear way.
• Improved Diagram Accuracy: Regular practice helps you master labeled diagrams that carry direct marks.
• Better Application Skills: Strengthens your ability to answer reasoning and case-based questions.
• Enhanced Retention: Organizing information through flowcharts and notes improves long-term memory.
• Exam-Ready Practice: Covers frequently asked topics from the NCERT syllabus and board papers.

FAQs

Q1. How many marks are usually allotted to this chapter in the Class 10 Science exam?

Ans. This chapter generally carries 6 to 8 marks and often includes diagram-based questions.

Q2. Which topics are most important for exams?

Ans. Human reproductive systems, sexual reproduction in flowering plants, fertilization, and contraceptive methods are key topics for board exams.

Q3. Are diagrams compulsory in long answers?

Ans. They are not compulsory in every question but highly recommended. Well-labeled diagrams make your answers clearer and can fetch full marks.

Q4. How should I prepare the human reproductive system?

Ans. Learn the names and functions of all major organs. Practise drawing both male and female reproductive systems neatly and label them correctly.

Q5. How can I remember the sequence of reproductive processes easily?

Ans. Use simple flowcharts for processes like pollination → fertilization → zygote → embryo → seed formation. Rewriting them helps reinforce the sequence.