Question Detail
Question
What structure prevents polyspermy during fertilization?
Correct Answer
Option A is the correct answer.
Detailed Explanation
The cortical reaction is a rapid release of cortical granules from the egg's cytoplasm upon sperm entry. Their contents cause changes in the egg's outer layers (like the zona pellucida hardening), making it impermeable to other sperm.
Hint
It's a fast block to multiple sperm entering.