The second maturation division of the mammalian ovum occurs

Options

A. In the Graafian follicle following the first maturation division
B. Shortly after ovulation before the ovum makes entry into the fallopian tube
C. Until after the ovum has been penetrated by a sperm
D. Until the nucleus of the sperm has fused with that of the ovum

Answer

C

Explanation

In mammalian ovum during maturation phase, meiosis occurs, nucleus shifts towards animal pole and undergoes meiosis-I. After fertilization (penetration of sperm), the second meiotic division is completed with unequal cytoplasmic cleavage. This forms a large cell the ootid with essentially whole of the cytoplasm and a very small cell, the second polar body.