What eases the entry of the sperm nucleus through the plasma membrane into the ovum?

a) activation of ovum

b) cortical reaction

c) acrosome reaction

The entry of the sperm nucleus is facilitated by C) acrosome reaction. The acrosome is the head-like structure at the front of the sperm cell. This contains digestive enzymes that break down the outer membrane of the egg cell, allowing the nucleus of the sperm cell to enter and fuse with the nucleus of the egg cell.