Polyspermy block occurs as a result of the:

Ans. A. Cortical reactiona. Fertilization by more than one sperm is prevented by the cortical reaction. Cortical granules containing proteolytic enzymes fuse just beneath the entire surface of the oolemma.b. The proteolytic enzymes are released to the perivitelline space, destroy the sperm receptors, and harden the zona, preventing other sperm from penetrating the fertilized ovum. Enzyme reaction is a nonspecific term with little meaning for polyspermy.c. The acrosome reaction allows the sperm to penetrate the zona. The decidual reaction is an inflammatory-like reaction that occurs simultaneously with implantation of the blastocyst into the uterine endometrium.