Oogenesis is initiated in the foetal ovary before the birth of girl child but gets temporarily arrested before birth at:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Prophase-I of Meiosis-I of primary oocytes
Oogenesis starts before birth. Millions of gamete mother cells, the oogonia, form in the foetal ovary, and no more are added after birth. These cells begin meiosis, enter prophase of the first meiotic division and are held there. A cell held at this stage is called a primary oocyte.
(1) Metaphase-I of Meiosis-I of primary oocytes — Incorrect. The cells do not go beyond prophase before birth. The first division is completed much later, just before ovulation.
(2) Prophase-I of Meiosis-I of primary oocytes — Correct. The primary oocytes stay arrested at this stage until puberty.
(3) Anaphase-II of Meiosis-II of primary oocytes — Incorrect. The second meiotic division starts only in the secondary oocyte, after the first division is over. That does not happen before birth.
(4) Metaphase-II of Meiosis-II of primary oocytes — Incorrect. A primary oocyte has not even finished the first division, so it cannot be in the second.
NCERT Extract:
Gametogenesis – …
