Pregnancy begins with the implantation of:

$A$ change in the amount of yolk and its distribution in the egg will affect

Fertilisation takes place in . . . . . . of Human.

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.

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.

In the human embryo, where are the extra-embryonic membranes formed?