The phenomenon of fertilization was first perceived by

In the beginning of menstruation what will happen?

$A$ : All copulations do not lead to fertilisation and pregnancy.
$R$ : Fertilisation can occur if the ovum and sperms are transported simultaneously to the ampullary-isthmic junction

$FSH $ acts on ........, which help in the process of spermiogenesis.

Number of sperms present in a single ejaculation of semen contains

During the fourth and sixth cleavage of the zygote