Meiotic division of the secondary oocyte is completed:
Answer: (B) At the time of fusion of a sperm with an ovum. Answer: (B) At the time of fusion of a sperm with an ovum Solution: NCERT states the secondary oocyte enters the ovary still arrested; the second meiotic division of the secondary oocyte is completed only when the sperm enters and contacts the ovum, which induces completion of meiosis forming the second polar body and the haploid ovum.
- A.After zygote formation
- B.At the time of fusion of a sperm with an ovum✓
- C.Prior to ovulation
- D.At the time of copulation
Correct Answer
(B) At the time of fusion of a sperm with an ovum
Solution & Explanation
Answer: (B) At the time of fusion of a sperm with an ovum Solution: NCERT states the secondary oocyte enters the ovary still arrested; the second meiotic division of the secondary oocyte is completed only when the sperm enters and contacts the ovum, which induces completion of meiosis forming the second polar body and the haploid ovum. Therefore meiosis of the secondary oocyte is completed at the time of fusion of sperm with ovum. Answer is NCERT-grounded as the 2020 paper had no printed biology key. NCERT Reference: Ch 2, p.36, line 4 — "membrane. This induces the completion of the meiotic division of the"