Class 9 · Science · Biology
Reproduction: How Life Continues
NCERT-style practice worksheet | Conceptual understanding, application and examination practice
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Read the chapter notes to refresh important concepts and diagrams.
Suggested time90 minutes
Maximum marks50 marks
SubjectScience
General Instructions
- Attempt all sections.
- Read each question carefully before answering.
- Draw neat, labelled diagrams wherever required.
- Write scientific terms accurately and support explanations with suitable examples.
- The answer key and hints are provided at the end. Try the worksheet before checking them.
Section A
Multiple Choice Questions
10 × 1 = 10 marks1. Which of the following is an example of vegetative propagation?
2. The small outgrowth formed during budding is called:
3. In Rhizopus, spores are produced inside the:
4. The type of cell division that generally produces genetically identical daughter cells is:
5. Which part of a flower receives pollen grains?
6. The fusion of male and female gametes is known as:
7. In human beings, fertilisation usually takes place in the:
8. Which of the following contains 23 chromosomes in humans?
9. The release of a mature egg from an ovary is called:
10. Which contraceptive method also helps reduce the risk of many sexually transmitted infections?
Section B
Assertion–Reason Questions
4 × 1 = 4 marksFor Questions 11–14, 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.
11. Assertion: Vegetative propagation generally produces genetically identical plants.
Reason: It involves only one parent and does not involve fusion of gametes.
Reason: It involves only one parent and does not involve fusion of gametes.
12. Assertion: Cross-pollination can increase genetic variation in plants.
Reason: Pollen is transferred between flowers on different plants of the same species.
Reason: Pollen is transferred between flowers on different plants of the same species.
13. Assertion: The chromosome number of a species generally remains constant from one generation to the next in sexual reproduction.
Reason: Meiosis reduces the chromosome number in gametes to half, and fertilisation restores it.
Reason: Meiosis reduces the chromosome number in gametes to half, and fertilisation restores it.
14. Assertion: Oral contraceptive pills protect a person from sexually transmitted infections.
Reason: Oral contraceptive pills alter hormonal activity to help prevent pregnancy.
Reason: Oral contraceptive pills alter hormonal activity to help prevent pregnancy.
Section C
Very Short Answer Questions
5 × 2 = 10 marks15. Define reproduction. State one reason why it is important for living organisms.
16. What are clones? Name the type of cell division generally associated with their formation.
17. What is the difference between pollination and fertilisation?
18. Name the male and female reproductive parts of a flower. Mention one structure present in each.
19. What is implantation? Where does it take place in human beings?
Section D
Short Answer Questions
4 × 3 = 12 marks20. Explain any three methods of artificial vegetative propagation. Give one example wherever appropriate.
21. Describe the process of spore formation in Rhizopus. Why are spores produced in large numbers?
22. Differentiate between external and internal fertilisation on the basis of:
- Site of fertilisation
- Examples of animals
- Number of eggs generally produced and chances of survival
23. Explain the role of meiosis in sexual reproduction. Why is it important for maintaining the chromosome number of a species?
Section E
Long Answer Questions
2 × 4 = 8 marks24. Describe sexual reproduction in flowering plants under the following headings:
- Pollination
- Germination of pollen on the stigma
- Growth of the pollen tube and fertilisation
- Changes in the ovule and ovary after fertilisation
25. Describe the main stages of the human menstrual cycle in a typical 28-day cycle. Explain what happens when the egg is not fertilised.
Section F
Competency-Based and Case-Based Questions
2 × 3 = 6 marks
Case Study 1: Choosing a method of plant propagation
A farmer wants to grow a large number of banana plants with desirable characteristics. The farmer wants the plants to be uniform and ready for cultivation in a shorter time. A horticulturist suggests tissue culture as a suitable method.
26.
- What is tissue culture? (1)
- Why is tissue culture suitable for producing a large number of similar plants? (1)
- State one possible limitation of producing crops with very little genetic variation. (1)
Case Study 2: Fertilisation and reproductive health
A student learns that a human sperm and egg each contain 23 chromosomes. During fertilisation, they fuse to form a zygote. The student also learns that some contraceptive methods prevent pregnancy but do not protect against sexually transmitted infections.
27.
- How many chromosomes are present in the human zygote? (1)
- Why do sperm and egg cells contain half the chromosome number of body cells? (1)
- Name a contraceptive method that helps reduce the risk of many sexually transmitted infections. (1)
Section G
Diagram and Application Questions
Optional practice28. Draw a neat, labelled diagram of a bisexual flower. Label the following parts: anther, filament, stigma, style, ovary and ovule.
29. Draw a labelled diagram to show budding in Hydra. Briefly describe the stages shown in your diagram.
30. A student claims that ovulation always occurs on the 14th day of every menstrual cycle. Is this statement correct? Give two reasons to support your answer.
Answer Key and Hints
Check your responses only after completing the worksheet. For descriptive questions, answers may be written in your own words if the scientific meaning is correct.
Section A – Multiple Choice Questions
1. (c) New plants from potato tubers. Potato reproduces vegetatively through buds or eyes on its stem tuber.
2. (b) Bud.
3. (c) Sporangium.
4. (b) Mitosis.
5. (c) Stigma.
6. (b) Fertilisation.
7. (c) Oviduct.
8. (b) Sperm cell.
9. (c) Ovulation.
10. (c) Condoms.
Section B – Assertion–Reason
11. (a) Both statements are true, and the reason explains why vegetative propagation generally produces genetically identical plants.
12. (a) Both statements are true. Cross-pollination transfers pollen between different plants of the same species and can increase variation.
13. (a) Both statements are true. Meiosis halves the chromosome number, and fertilisation restores it.
14. (d) The assertion is false, but the reason is true. Oral pills help prevent pregnancy but do not protect against STIs.
Section C – Very Short Answers
15. Reproduction is the biological process by which living organisms produce new individuals of their own kind. It ensures the continuity of a species.
16. Clones are genetically identical individuals. They are generally formed through mitosis during asexual reproduction.
17. Pollination is the transfer of pollen from anther to stigma. Fertilisation is the fusion of male and female gametes.
18. Stamen is the male reproductive part and contains anther and filament. Pistil is the female reproductive part and contains stigma, style and ovary.
19. Implantation is the attachment of the developing embryo to the inner lining of the uterus.
Section D – Short Answers
20. Any three:
- Cutting: A piece of stem is planted in suitable soil and develops roots and shoots.
- Grafting: A stem piece from one plant is joined to the rooted plant of another.
- Layering: A branch is bent and partly covered with soil until roots develop.
- Tissue culture: Plantlets are grown from small pieces of plant tissue under controlled conditions.
21. Rhizopus produces spores inside a sporangium borne at the tip of an upright hypha. On maturity, the sporangium releases spores. They are dispersed through air and germinate under favourable conditions. Large numbers are produced because many spores do not reach suitable conditions.
22.
- External fertilisation: Fusion occurs outside the female body; examples include many fish and frogs. Usually many eggs are released, and survival is often lower.
- Internal fertilisation: Fusion occurs inside the female body; examples include reptiles, birds and mammals. Generally fewer eggs or young are produced, with greater protection during development.
23. Meiosis reduces the chromosome number to half during gamete formation. When haploid gametes fuse during fertilisation, the diploid chromosome number is restored. This prevents the chromosome number from doubling in every generation.
Section E – Long Answers
24.
- Pollination transfers pollen grains from anther to stigma.
- A compatible pollen grain germinates on the stigma and forms a pollen tube.
- The pollen tube grows through the style towards the ovary. The male gamete reaches the ovule and fuses with the egg cell to form a zygote.
- The zygote develops into an embryo, the ovule becomes a seed and the ovary develops into a fruit.
25.
- Days 1–5: Menstruation; the uterine lining is shed.
- Days 6–14: The uterine lining rebuilds and an egg matures.
- Around day 14: Ovulation may occur.
- Days 15–28: The uterine lining becomes thicker and richer in blood vessels.
Section F – Case-Based Questions
26.
- Tissue culture is a method of producing new plants from small pieces of plant tissue under controlled laboratory conditions.
- It allows a large number of similar plantlets to be produced from selected plant material.
- Low genetic variation may make the crop more vulnerable if a disease or environmental change affects that variety.
27.
- 46 chromosomes.
- Gametes are formed through meiosis, which reduces the chromosome number to half. Fertilisation restores the diploid number.
- Condoms.
Section G – Diagram and Application
28. The diagram should correctly show and label the anther and filament (stamen), and stigma, style, ovary and ovule (pistil).
29. The diagram should show a small bud developing on the body of Hydra, growing larger and eventually separating from the parent. The bud develops through repeated cell division.
30. No. Day 14 is an approximate reference for a typical 28-day cycle. Menstrual cycles may be shorter or longer, and ovulation does not occur on the same day in every cycle. The timing can vary from one person to another and between cycles.
Self-assessment: Review the questions you could not answer confidently. Revisit the corresponding topic in the chapter notes, practise the labelled diagrams and attempt the questions again without looking at the hints.