About This Section

This section collects questions of the type asked in CBSE and other board examinations on How Do Organisms Reproduce?. Studying them helps you learn the pattern (what is asked), the mark distribution, and the answer style examiners expect.

Study Strategy:

  1. Try each question yourself first.
  2. Match answer length to the marks (1-mark = 1–2 lines; 2-mark = 2–3 points; 3-mark = 5–6 points/labelled diagram; 5-mark = detailed answer with diagram).
  3. Draw diagrams neatly (flower L.S., male system, female system).
  4. Use the exact NCERT terms — examiners reward the standard vocabulary.

Questions below are grouped by mark level.

1-Mark Questions (MCQ / Very Short)

Q1. [CBSE] Budding as a method of asexual reproduction is found in — (a) Amoeba (b) Yeast (c) Plasmodium (d) Spirogyra

Solution: (b) Yeast. Yeast forms buds that detach and grow into new individuals.

Q2. [CBSE] The anther of a flower contains — (a) sepals (b) ovules (c) pollen grains (d) pistil

Solution: (c) pollen grains. The anther is the male part that produces pollen.

Q3. [CBSE] Which one is not a part of the female reproductive system? (a) Ovary (b) Oviduct (c) Uterus (d) Vas deferens

Solution: (d) Vas deferens — it belongs to the male system.

Q4. [CBSE] In humans, fertilisation takes place in the — (a) uterus (b) ovary (c) oviduct (d) vagina

Solution: (c) oviduct (fallopian tube).

1-Mark Questions (continued)

Q5. [CBSE] Name the part of the flower that develops into the fruit.

Solution: The ovary develops into the fruit after fertilisation.

Q6. [CBSE] Why are the testes located in the scrotum, outside the abdomen?

Solution: Because sperm formation needs a temperature lower than body temperature, which the scrotum provides.

Q7. [CBSE] Which contraceptive method also helps prevent sexually transmitted diseases?

Solution: Barrier methods (condoms).

Q8. [CBSE] Name one bacterial and one viral sexually transmitted disease.

Solution: Bacterial — syphilis (or gonorrhoea); Viral — HIV–AIDS (or warts).

2-Mark Questions

Q9. [CBSE] How does binary fission differ from multiple fission?

Solution:

  • Binary fission: parent divides into two daughter cells (Amoeba, bacteria).
  • Multiple fission: parent divides into many daughter cells at once (Plasmodium).

Q10. [CBSE] Differentiate between self-pollination and cross-pollination.

Solution:

  • Self-pollination: pollen transferred to the stigma of the same flower.
  • Cross-pollination: pollen transferred from one flower to another, usually by wind, water or animals.

2-Mark Questions (continued)

Q11. [CBSE] What is the role of the seminal vesicles and the prostate gland?

Solution: They add secretions to the sperms that make their transport easier and provide nutrition. (Sperms + this fluid = semen.)

Q12. [CBSE] Why is variation beneficial to a species?

Solution: Variation lets some individuals survive changes in the environment (temperature, water level, etc.). Thus variation ensures the survival of the species over time and is the basis of evolution.

Q13. [CBSE] State two advantages of vegetative propagation.

Solution: (1) Plants that have lost the ability to make seeds (banana, rose) can still be grown. (2) The offspring are genetically identical to the parent, and may flower/fruit earlier.

3-Mark Questions

Q14. [CBSE] Distinguish between pollination and fertilisation. Which occurs first?

Solution:

  • Pollination: transfer of pollen from anther to stigma. No gamete fusion.
  • Fertilisation: fusion of the male germ-cell (from pollen) with the egg in the ovule, forming a zygote.
  • Pollination occurs first, followed by fertilisation.

Q15. [CBSE] Describe the structure and function of the placenta.

Solution:

  • Structure: a disc-shaped tissue embedded in the uterine wall; it has villi on the embryo's side and blood spaces on the mother's side, giving a large surface area.
  • Function: glucose and oxygen pass from mother to embryo; wastes pass from embryo to mother.

3-Mark Questions (continued)

Q16. [CBSE] List the different methods of contraception (one line each).

Solution:

  1. Barrier — condoms; block sperm and also reduce STDs.
  2. Hormonal — oral pills; stop egg release.
  3. IUCD — loop / copper-T placed in uterus.
  4. Surgical — vasectomy (block vas deferens) / tubectomy (block fallopian tube).

Q17. [CBSE] Why does menstruation occur? How long does it usually last?

Solution: Each month the uterus builds a thick, spongy, blood-rich lining to receive a fertilised egg. If the egg is not fertilised, this lining breaks down and is shed as blood and mucus through the vagina. It usually lasts about 2–8 days.

Q18. [CBSE] "Regeneration is not the same as reproduction." Justify with an example.

Solution: In regeneration (e.g. Planaria, Hydra), body pieces can grow into complete organisms via specialised cells. But organisms do not normally rely on being cut up to multiply, so it is not their regular means of producing offspring — hence it is not reproduction.

5-Mark Questions

Q19. [CBSE] (a) Draw a labelled diagram of the longitudinal section of a flower. (b) Name its male and female reproductive parts and their sub-parts.

Solution: (a) Draw the L.S. of a flower and label: sepal, petal, stamen (anther + filament), pistil (stigma + style + ovary), ovule. (b)

  • Male part — Stamen: consists of anther (produces pollen) and filament.
  • Female part — Pistil: consists of stigma (receives pollen), style, and ovary (contains ovules, each with an egg cell).

Q20. [CBSE] Describe sexual reproduction in a flowering plant from pollination to seed formation.

Solution:

  1. Pollination: pollen is transferred from anther to stigma (self or cross).
  2. A pollen tube grows from the pollen grain through the style to the ovary.
  3. Fertilisation: the male germ-cell fuses with the egg in the ovule → zygote.
  4. The zygote divides to form an embryo within the ovule.
  5. The ovule → seed (tough coat) and the ovary → fruit; other flower parts shrivel and fall.

5-Mark Questions (continued)

Q21. [CBSE] (a) Draw and label the human male reproductive system OR describe its parts. (b) Trace the path of a sperm.

Solution: (a) Parts and functions:

  • Testes (in scrotum) — produce sperms + secrete testosterone; kept cooler than body temperature.
  • Vas deferens — carries sperms.
  • Seminal vesicle + prostate — add fluid (transport + nutrition).
  • Urethra — common passage for sperm and urine.
  • Penis — delivers sperm.

(b) Path: Testes → vas deferens → urethra → penis.

Q22. [CBSE] Explain how the human female body is prepared each month for a possible pregnancy, and what happens if fertilisation does not occur.

Solution:

  • One ovary releases one egg per month; the egg travels into the oviduct.
  • The uterus lining thickens (spongy, blood-rich) to receive and nourish an embryo.
  • If fertilised: the embryo implants in the uterus and develops, nourished by the placenta (~9 months, then birth by uterine contractions).
  • If not fertilised: the egg lives ~1 day; the thick lining is not needed and breaks down, shed as menstruation (blood + mucus, ~2–8 days).