Meiotic division of the secondary oocyte is completed
- At the time of fusion of a sperm with an ovum
- At the time of copulation
- Prior to ovulation
- After zygote formation
Answer
(1) At the time of fusion of a sperm with an ovum
Solution
As per NCERT, the ovum is released from the Graafian follicle as a secondary oocyte (arrested in meiosis II).
⇒ The entry of the sperm into the ovum induces completion of the meiotic division of the secondary oocyte.
⇒ This forms the haploid ovum (ootid) and the second polar body; the haploid nuclei of sperm and ovum then fuse to form the diploid zygote.
∴ Meiosis II is completed at the time of fusion of a sperm with the ovum.
Answer: (1)