Class 9 Science Important Questions and Answers: Reproduction — How Life Continues
Premium NCERT, Board Exam, Exemplar and Olympiad-level question answers for Class 9 Science. Learn reproduction in plants and animals, sexual and asexual reproduction, male and female reproductive organs, sexually transmitted diseases and pregnancy prevention methods in a student-friendly CBSE format.
Short Introduction
Reproduction is the biological process by which living organisms produce new individuals of their own kind. It is essential for the continuation of species and transfer of characters from parents to offspring.
In this chapter, students learn about asexual and sexual reproduction in plants and animals, human reproductive organs, fertilisation, pregnancy, sexually transmitted diseases and responsible pregnancy prevention methods.
Exam focus: Importance of reproduction, types of reproduction, reproductive organs, pollination, fertilisation, seed formation, STDs and contraception are important for CBSE exams.
Chapter Overview
1. Reproduction
Process by which organisms produce young ones of their own kind.
2. Asexual Reproduction
Only one parent is involved and no fusion of gametes takes place.
3. Sexual Reproduction
Two parents are usually involved and male and female gametes fuse.
4. Reproduction in Plants
Plants reproduce by vegetative propagation, spores, flowers, seeds and fruits.
5. Reproduction in Animals
Animals reproduce through male and female reproductive systems.
6. Reproductive Health
Includes STDs, hygiene, responsible behaviour and pregnancy prevention methods.
Important Keywords
Important Concepts at a Glance
Reproduction
Living organisms produce new individuals.
Asexual Reproduction
One parent, no gamete fusion.
Sexual Reproduction
Fusion of male and female gametes.
Fertilisation
Sperm + Egg → Zygote
Male Gamete
Sperm in animals, pollen-related male gamete in plants.
Female Gamete
Ovum in animals, egg cell in plants.
Pollination
Transfer of pollen from anther to stigma.
Contraception
Methods used to prevent unwanted pregnancy.
Important note: Reproductive health topics should be studied scientifically, respectfully and responsibly. Pregnancy prevention and STD prevention must always be understood with correct health guidance.
Important Very Short Answer Questions
Q1. What is reproduction?
Answer: Reproduction is the biological process by which living organisms produce new individuals of their own kind.
Q2. Why is reproduction important?
Answer: Reproduction is important because it ensures the continuation of species generation after generation.
Q3. Name the two main types of reproduction.
Answer: The two main types of reproduction are asexual reproduction and sexual reproduction.
Q4. What is asexual reproduction?
Answer: Asexual reproduction is a type of reproduction in which only one parent is involved and no fusion of gametes occurs.
Q5. What is sexual reproduction?
Answer: Sexual reproduction is a type of reproduction in which male and female gametes fuse to form a zygote.
Q6. What is fertilisation?
Answer: Fertilisation is the fusion of male and female gametes to form a zygote.
Q7. What is a zygote?
Answer: A zygote is the single cell formed after fertilisation.
Q8. Name the male reproductive organ in flowering plants.
Answer: The male reproductive organ in flowering plants is the stamen.
Q9. Name the female reproductive organ in flowering plants.
Answer: The female reproductive organ in flowering plants is the pistil or carpel.
Q10. Name the male gamete in humans.
Answer: The male gamete in humans is sperm.
Q11. Name the female gamete in humans.
Answer: The female gamete in humans is ovum or egg.
Q12. What are STDs?
Answer: STDs are sexually transmitted diseases that spread mainly through sexual contact with an infected person.
Q13. Give two examples of STDs.
Answer: HIV/AIDS and syphilis are examples of sexually transmitted diseases.
Q14. What is contraception?
Answer: Contraception means methods used to prevent unwanted pregnancy.
Short Answer Questions
Q1. Differentiate between asexual and sexual reproduction.
Answer:
| Asexual Reproduction | Sexual Reproduction |
|---|---|
| Only one parent is involved. | Usually two parents are involved. |
| No fusion of gametes takes place. | Fusion of male and female gametes takes place. |
| Offspring are usually identical to parent. | Offspring show variations. |
| Example: binary fission in Amoeba. | Example: reproduction in humans. |
Q2. Write any three advantages of reproduction.
Answer:
- It ensures the continuity of species.
- It produces new individuals of the same kind.
- It transfers hereditary characters from parents to offspring.
- Sexual reproduction produces variations, which help in adaptation and evolution.
Q3. What is binary fission? Give one example.
Answer: Binary fission is an asexual method of reproduction in which one parent cell divides into two daughter cells. Example: Amoeba.
Q4. What is budding? Give one example.
Answer: Budding is an asexual method in which a small outgrowth called bud develops on the parent body and later separates to form a new individual. Example: Hydra or yeast.
Q5. What is vegetative propagation?
Answer: Vegetative propagation is a method of asexual reproduction in plants in which new plants are produced from vegetative parts like root, stem or leaf.
Q6. Write two advantages of vegetative propagation.
Answer:
- It helps in producing plants quickly.
- Plants produced are genetically similar to the parent plant.
- It helps in reproduction of plants that do not produce viable seeds.
Q7. What is pollination?
Answer: Pollination is the transfer of pollen grains from the anther to the stigma of a flower.
Q8. Differentiate between self-pollination and cross-pollination.
Answer:
| Self-Pollination | Cross-Pollination |
|---|---|
| Pollen is transferred to the stigma of the same flower or another flower of the same plant. | Pollen is transferred to the stigma of a flower on another plant of the same species. |
| It produces less variation. | It produces more variation. |
| Usually does not require external agents. | Usually requires agents like wind, water or insects. |
Q9. Why is sexual reproduction important for evolution?
Answer: Sexual reproduction produces variations among offspring. These variations help organisms adapt to changing environments and contribute to evolution.
Q10. Why should STDs be prevented?
Answer: STDs should be prevented because they can seriously affect reproductive health, general health and may spread from one person to another.
Male and Female Reproductive Organs
| System | Organ | Main Function |
|---|---|---|
| Male reproductive system | Testes | Produce sperms and male hormone testosterone. |
| Male reproductive system | Sperm duct | Transports sperms. |
| Male reproductive system | Penis | Helps in transfer of sperms. |
| Female reproductive system | Ovaries | Produce ova and female hormones. |
| Female reproductive system | Oviduct or fallopian tube | Site where fertilisation usually takes place. |
| Female reproductive system | Uterus | Place where embryo develops during pregnancy. |
| Female reproductive system | Vagina | Birth canal and passage connected to the uterus. |
Long Answer Questions
Q1. Explain different methods of asexual reproduction with examples.
Answer: Asexual reproduction involves only one parent and does not involve fusion of gametes.
- Binary fission: One parent cell divides into two daughter cells. Example: Amoeba.
- Budding: A bud develops on the parent body and grows into a new organism. Example: Hydra, yeast.
- Fragmentation: Body breaks into fragments and each fragment grows into a new organism. Example: Spirogyra.
- Spore formation: Spores are formed and later develop into new individuals. Example: Rhizopus.
- Vegetative propagation: New plants arise from root, stem or leaf. Example: potato, rose, sugarcane.
Q2. Explain sexual reproduction in flowering plants.
Answer:
- The flower is the reproductive part of a plant.
- The stamen is the male reproductive part and produces pollen grains.
- The pistil or carpel is the female reproductive part and contains stigma, style and ovary.
- Pollination transfers pollen grains from anther to stigma.
- Male gamete fuses with female gamete inside the ovule. This is called fertilisation.
- After fertilisation, the ovule develops into a seed and the ovary develops into a fruit.
Q3. Explain the male reproductive system in humans.
Answer:
- The male reproductive system produces and transports sperms.
- Testes: Produce sperms and testosterone.
- Scrotum: Holds testes outside the body and maintains suitable temperature for sperm formation.
- Sperm ducts: Carry sperms from testes.
- Glands: Add fluids to sperms to form semen.
- Penis: Helps in transfer of sperms into the female reproductive tract.
Q4. Explain the female reproductive system in humans.
Answer:
- The female reproductive system produces ova and supports development of the embryo.
- Ovaries: Produce ova and female hormones.
- Oviducts or fallopian tubes: Carry the ovum and are the usual site of fertilisation.
- Uterus: A muscular organ where the embryo develops during pregnancy.
- Vagina: Connects the uterus to the outside and acts as the birth canal.
Q5. What happens after fertilisation in humans?
Answer:
- Fertilisation occurs when sperm fuses with ovum to form a zygote.
- The zygote divides repeatedly to form an embryo.
- The embryo gets implanted in the wall of the uterus.
- The embryo receives nutrition from the mother through the placenta.
- The development of embryo into a baby takes place during pregnancy.
Q6. What are sexually transmitted diseases? How can they be prevented?
Answer: Sexually transmitted diseases are infections that spread mainly through sexual contact with an infected person.
Examples: HIV/AIDS, syphilis, gonorrhoea, hepatitis B and genital herpes.
Prevention:
- Follow responsible and informed behaviour.
- Use medically approved protection such as condoms.
- Avoid sharing needles or syringes.
- Go for medical testing and treatment when required.
- Maintain reproductive hygiene and awareness.
Q7. Explain pregnancy prevention methods.
Answer: Pregnancy prevention methods are also called contraceptive methods. They help prevent unwanted pregnancy.
- Barrier methods: Condoms prevent sperms from reaching the egg and also reduce the risk of many STDs.
- Hormonal methods: Pills or hormonal devices prevent ovulation or fertilisation. These should be used only under medical guidance.
- Intrauterine devices: Devices placed in the uterus by a trained medical professional to prevent pregnancy.
- Surgical methods: Permanent methods such as vasectomy and tubectomy are used by adults who do not want more children.
- Awareness and counselling: Correct knowledge and medical advice help in responsible reproductive health decisions.
Case-Study Based Questions
Case Study 1: Reproduction in Flowering Plants
A student observes a flower and identifies anther, stigma, style, ovary and ovules. Pollen grains are transferred from the anther to the stigma. Later, fertilisation takes place and seeds are formed.
Q1. What is the transfer of pollen grains from anther to stigma called?
Answer: It is called pollination.
Q2. Which part of the flower produces pollen grains?
Answer: The anther produces pollen grains.
Q3. What does the ovule develop into after fertilisation?
Answer: The ovule develops into a seed.
Q4. What does the ovary develop into after fertilisation?
Answer: The ovary develops into a fruit.
Case Study 2: Human Reproduction
In humans, sperms are produced in testes and ova are produced in ovaries. Fertilisation usually occurs in the oviduct. The zygote formed after fertilisation divides and develops into an embryo.
Q1. Where are sperms produced?
Answer: Sperms are produced in the testes.
Q2. Where are ova produced?
Answer: Ova are produced in the ovaries.
Q3. Where does fertilisation usually occur?
Answer: Fertilisation usually occurs in the oviduct or fallopian tube.
Q4. What is formed after fertilisation?
Answer: A zygote is formed after fertilisation.
Case Study 3: Reproductive Health
A health educator explains that reproductive health includes awareness, hygiene, prevention of sexually transmitted diseases and responsible pregnancy prevention methods. The educator also explains that some infections can spread through unsafe sexual contact and infected needles.
Q1. What are diseases spread mainly through sexual contact called?
Answer: They are called sexually transmitted diseases or STDs.
Q2. Name one STD.
Answer: HIV/AIDS is one example of an STD.
Q3. Which barrier method helps reduce the risk of many STDs?
Answer: Condoms help reduce the risk of many STDs.
Q4. Why is reproductive health education important?
Answer: It helps students understand hygiene, disease prevention and responsible health decisions.
Assertion-Reason Questions
Choose the correct option:
A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
C. Assertion is true but Reason is false.
D. Assertion is false but Reason is true.
Q1. Assertion: Reproduction is necessary for the continuation of species.
Reason: Reproduction produces new individuals of the same kind.
Answer: A. Both are true and Reason correctly explains Assertion.
Q2. Assertion: Asexual reproduction produces more variation than sexual reproduction.
Reason: Asexual reproduction involves only one parent and no fusion of gametes.
Answer: D. Assertion is false but Reason is true.
Q3. Assertion: Pollination and fertilisation are the same process.
Reason: Pollination is the transfer of pollen from anther to stigma.
Answer: D. Assertion is false but Reason is true.
Q4. Assertion: Sexual reproduction helps in evolution.
Reason: Sexual reproduction produces variations in offspring.
Answer: A. Both are true and Reason correctly explains Assertion.
Q5. Assertion: Testes produce sperms.
Reason: Sperms are male gametes.
Answer: A. Both are true and Reason correctly explains Assertion.
Q6. Assertion: Condoms can help reduce the risk of many STDs.
Reason: Condoms act as a barrier method.
Answer: A. Both are true and Reason correctly explains Assertion.
Exam Tips
- Write the definition of reproduction clearly with the phrase “own kind”.
- Use a table to differentiate between sexual and asexual reproduction.
- Learn examples of asexual reproduction: Amoeba, Hydra, yeast, Spirogyra and Rhizopus.
- For plant reproduction, remember: anther → pollen, stigma → receives pollen, ovule → seed, ovary → fruit.
- In human reproduction questions, write organ names and functions point-wise.
- Do not confuse pollination with fertilisation.
- For reproductive health, use scientific and respectful language.
- Write STD prevention points in a responsible health-awareness format.
- Mention that medical methods of pregnancy prevention should be used under proper medical guidance.
Quick Revision Box
Reproduction
Process of producing new individuals of the same kind.
Asexual Reproduction
One parent, no fusion of gametes, less variation.
Sexual Reproduction
Fusion of male and female gametes, more variation.
Pollination
Transfer of pollen grains from anther to stigma.
Fertilisation
Fusion of male and female gametes to form zygote.
Zygote
First cell formed after fertilisation.
Testes
Produce sperms and testosterone.
Ovaries
Produce ova and female hormones.
Uterus
Organ where embryo develops during pregnancy.
STDs
Diseases spread mainly through sexual contact.
Contraception
Methods used to prevent unwanted pregnancy.
Variation
Differences among offspring, important for evolution.
FAQ Section
What is the main focus of Reproduction — How Life Continues?
The main focus is reproduction in plants and animals, sexual and asexual reproduction, reproductive organs, STDs and pregnancy prevention methods.
Why is reproduction important?
Reproduction is important because it ensures the continuation of species and transfer of characters from parents to offspring.
What is the difference between sexual and asexual reproduction?
Asexual reproduction involves one parent and no gamete fusion, while sexual reproduction involves fusion of male and female gametes.
What is pollination?
Pollination is the transfer of pollen grains from the anther to the stigma of a flower.
What is fertilisation?
Fertilisation is the fusion of male and female gametes to form a zygote.
What are the male reproductive organs in humans?
The main male reproductive organs include testes, sperm ducts, glands and penis.
What are the female reproductive organs in humans?
The main female reproductive organs include ovaries, oviducts, uterus and vagina.
What are sexually transmitted diseases?
Sexually transmitted diseases are infections that spread mainly through sexual contact with an infected person.
How can STDs be prevented?
STDs can be prevented through awareness, responsible behaviour, medically approved protection, avoiding infected needles and seeking medical care when required.
What are pregnancy prevention methods?
Pregnancy prevention methods include barrier methods, hormonal methods, intrauterine devices, surgical methods and proper medical counselling.
Why is reproductive health education important?
It helps students understand hygiene, disease prevention, responsible choices and scientific facts about reproduction.
Final Conclusion
Reproduction is a vital life process because it allows organisms to continue their species. Students should understand both asexual and sexual reproduction, plant reproduction, human reproductive organs, fertilisation and reproductive health.
To score well in CBSE exams, write definitions clearly, use labelled points, compare sexual and asexual reproduction in table form and revise reproductive health topics with scientific and respectful language.
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