Question

which of the following prevents polyspermy?
a.) acrosomal reaction
b.) capacitation
c.) union of pronuclei
d.) cortical reaction

Explanation:

Polyspermy is prevented by the cortical reaction. The cortical reaction involves the release of cortical granules from the egg, which modify the zona pellucida (the extracellular matrix surrounding the egg) to block additional sperm from binding and fusing with the egg.

• The acrosomal reaction helps sperm penetrate the egg's outer layers but does not prevent polyspermy.
• Capacitation is a process that makes sperm motile and able to fertilize an egg, not a polyspermy - prevention mechanism.
• The union of pronuclei occurs after fertilization (when the sperm and egg nuclei fuse) and is not related to preventing polyspermy.

Answer:

d. Cortical reaction