What will be the number of chromosomes in the gamete of maize if its…

The correct answer is Option (1) → 10

A meiocyte is diploid (2n). It divides by meiosis, which halves the chromosome number, so the gamete is haploid (n).

Maize meiocyte 2n = 20, so gamete n = 20 ÷ 2 = 10.

Option (1) 10 — Correct. Gametes are formed from meiocytes by meiosis, which halves the chromosome number. A maize meiocyte with 20 chromosomes therefore gives gametes with 10 chromosomes.

Option (2) 20 — Incorrect. This is the number in the meiocyte; meiosis halves it.

Option (3) 24 — Incorrect. 24 is the 2n number of rice.

Option (4) 40 — Incorrect. This doubles the number instead of halving it.

Note: This question is from Chapter 1, Reproduction in Organisms, of the pre-rationalised NCERT book. This chapter is not in the present NCERT book (2026-27). The extract below is from the pre-rationalised edition.

NCERT Extract (Pre-rationalised edition, Chapter 1, Reproduction in Organisms):
Gametogenesis – “… In diploid organisms, specialised cells called meiocytes (gamete mother cell) undergo meiosis. At the end of meiosis, only one set of chromosomes gets incorporated into each gamete.”