The zona pellucida (vitelline layer-sea urchin) prevents polyspermy AND allows same species fertilization? Where does acrosome reaction play a part? Bc I've been memorizing that acrosome reaction is the one that prevents polyspermy but in the bio DAT destroyer, it states that the vitelline layer is what prevents polyspermy. Is the acrosome reaction a process whereas the zona pellucida is the structure hence referring to the same thing? Please enlighten me.