Which one of the following statements about the cortical reaction in sea urchins is correct?
1
The entry of Ca2+ ions into the egg initiates development.
2
The exocytosed cortical granules during egg maturation contain the components of the zona pellucida.
3
The depolarization of the plasma membrane after sperm entry helps to block polyspermy.
4
The release of the cortical granules after sperm entry converts the vitelline membrane into the fertilization membrane which blocks polyspermy.