Yolk of egg in the vertebrates is formed in

Enzyme present in sperm acrosome to dissolve egg membrane is

Acrosome of sperm is formed from

$A$ : In human, ovum is alecithal type.
$R$ : It is almost free of yolk

How many eggs do you think were released by the ovary of a female dog which gave birth to $6$ puppies?

Nervous system in vertebrates develops from