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Class 9 Science: Reproduction, How Life Continues, 8 practice questions with answers

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These are 8 practice questions on Chapter 11, Reproduction: How Life Continues, of the new NCERT Class 9 Science textbook, Exploration (First Edition, April 2026). Each has a worked answer and the textbook page it comes from. They cover how many chromosomes mitosis gives each daughter cell, grafting and layering, spores, how meiosis halves the chromosome number, self- and cross-pollination, what becomes the fruit and the seed, and external and internal fertilisation in animals. Try each one before you open the answer.

These questions are our own, drafted with AI help, and the two calculations were re-computed by a test script, but no practising teacher has reviewed them yet. If you find a mistake, please tell us.

What the chapter says you need

Facts from the NCERT textbook (Exploration: Textbook of Science for Grade 9, Chapter 11, printed pages 208 to 227):

Asexual reproduction

Question 1. A cell with 24 chromosomes divides by mitosis. How many chromosomes does each daughter cell have, and are the daughter cells identical to the parent cell?

Answer: 24 in each daughter cell; yes, identical. Mitosis is the cell division behind asexual reproduction. It produces two daughter cells, each having the same number of chromosomes as the parent cell, so each has 24, and the offspring formed this way are genetically identical copies, or clones. (Mitosis and clones, page 212.)

Question 2. A farmer fixes a stem piece from a guava tree that gives sweet fruit into a slit in the stem of a strong, well-rooted guava plant, and ties the joint until it heals. What is this method called?

Answer: grafting. A stem piece of one plant is inserted into a slit in the stem of another, rooted plant, and the joint is protected until it heals. (Grafting, page 210.)

Question 3. A flexible twig of a jasmine bush is bent down and its middle part is buried in soil while it is still attached to the bush. Some days later, the buried part has grown roots. What is this method called, and what happens next?

Answer: layering. Once roots have grown from the buried part, the twig is cut from the parent and grows as a new plant. (Layering, page 210.)

Question 4. A pair of leather shoes kept in a damp, warm cupboard gets fuzzy patches of mould. Where did the mould come from?

Answer: from spores in the air. Moulds reproduce by tiny, light spores that float on air currents. When spores settle on a warm, moist surface, they grow into new mould. (Spores, page 212.)

Sexual reproduction

Question 5. The body cells of a certain plant have 38 chromosomes. How many chromosomes does each of its gametes have, and how many will the fertilised egg (zygote) have?

Answer: 19 in each gamete; 38 in the zygote. Meiosis halves the chromosome number to make the gametes: 38 ÷ 2 = 19. At fertilisation, two gametes fuse: 19 + 19 = 38, the full number again. (Meiosis, page 213; fertilisation and the zygote, page 216; why the number must be halved, page 212.)

Question 6. Pollen from the anther of one pumpkin plant's flower reaches the stigma of a flower on a different pumpkin plant. Is this self-pollination or cross-pollination?

Answer: cross-pollination. The pollen moved to a flower of another plant of the same type. If it had reached the stigma of the same flower, or of another flower on the same plant, it would have been self-pollination. (Self- and cross-pollination, page 216.)

Question 7. After fertilisation in a flower, which part becomes the fruit and which parts become the seeds?

Answer: the ovary becomes the fruit; the ovules become the seeds. The ovary surrounding the ovules enlarges into a fruit while the ovules develop into seeds inside it. (Fertilisation and seed formation, page 216.)

Question 8. One animal is a tortoise (a reptile) and the other is a rohu (a fish that lays eggs in water). Which one has internal fertilisation and which has external?

Answer: the tortoise has internal fertilisation; the rohu has external fertilisation. In reptiles, birds and mammals, fertilisation takes place inside the female's body; in most fish, eggs and sperm are released into the water and fertilisation happens outside the body. (Sexual reproduction in animals, page 218; Table 11.4.)

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Sources

All opened and read on 21 October 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page + 207.

The facts are from the textbook pages above. The questions and worked answers are our own, and the two calculations were re-computed by script. This guide is general information; follow your teacher and the textbook.