In spiral cleavage turn of spiral may be
Clockwise
Anticlockwise
$(a)$ and $(b)$ both
None of these
$A$ : 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
In the beginning of menstruation what will happen?
Site of fertilization in a mammal is ......
Tertiary egg membranes are lacking in mammals with the exception of the
Function of gynogamone$-I$ is