MICROANATOMY

Detailed explanation-1: -The entry of sperm breaks the metaphase arrest of the oocyte and hence the meiosis-II cell division completes forming the zygote and the second polar body. This entire process takes place only after the entry of sperm and before the completion of fertilization.

Detailed explanation-2: -The second polar body (haploid) fuses with a haploid daughter nucleus from division of the first polar body (diploid); 3. A daughter nucleus from division of the first polar body fuses with the pronucleus; or 4. Two haploid nuclei fuse from cleavage.

Detailed explanation-3: -During fertilization, the acrosome’s secretion helps the sperm to enter into the cytoplasm of the ovum. This induces the completion of the second meiotic division of the secondary oocyte. The second meiotic division results in the formation of a second polar body and a haploid ovum.