Q. What happens during fertilisation in humans after many sperms reach close to the ovum?
A) Cells of corona radiata trap all the sperms except one
B) Only two sperms nearest the ovum penetrate zona pellucida
C) Secretions of acrosome helps one sperm enter cytoplasm of ovum through zona pellucida
D) All sperms except the one nearest to the ovum lose their tails
Explanation
[Solution from source] When sperms reach the ovum, the acrosome releases enzymes that help a single sperm penetrate the zona pellucida and enter the ovum; changes in the zona then block other sperms. The corona radiata does not selectively trap sperms, only one (not two) sperm enters, and the other sperms do not lose their tails. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.