The fertilized egg divides by the process of

What triggers the acrosome reaction in a sperm?

The layer of the uterus which becomes much eroded due to placental villi is known as:

Following are some events occurring during the fertilization process. Arrange the $CORRECT$ sequence of events and choose the option given below.
$i$. Fertilizin-antifertilizin reaction.
$ii$. Cortical reaction.
$iii$. Acrosome reaction.
$iv$. Karyogamy.
$v$. Capacitation of sperms.

Assertion : During fertilization,only the head of the spermatozoa enters the egg.
Reason : If several spermatozoa hit the egg at the same time,all can enter the egg.

Which of the following participate in the formation of a zygote?