Question : Read the following statements and choose the correct option . Statement A: As the sperm head comes in contact with the ovum membrane , it causes opening of Na^+ channels to cause depolarisation Statement B : Cortical reaction and zona reaction constitute slow block to check polyspermy.

Question : Read the following statements and choose the correct option

1.	Question : Read the following statements and choose the correct option . Statement A: As the sperm head comes in contact with the ovum membrane , it causes opening of Na^+ channels to cause depolarisation Statement B : Cortical reaction and zona reaction constitute slow block to check polyspermy.
Answer» Both statements are correct Both statements are incorrect Statements A is correct but B is incorrect Statement A is incorrect but B is correct Solution :FAST block to checkpolyspermy. During fertilization a part of sperm enters into cytoplasm of ova. `Ca^(2+)` influx causes extrusion of cortical granules (cortical reaction) and ZONA reaction which makes the zona pellucida impervious to other sperms by destroying sperm receptors, LEADING to slow block to CHECK polyspermy