The fluid filled in the blastocoel cavity of blastula is

In humans, what is the ratio of the number of gametes produced from one male primary sex cell to the number of gametes produced from one female primary sex cell ?

Which one of the following list contains only the mesodermal structures

Ejaculation of semen

From where spermatogenesis starts ?

Eggs having yolk in their centre of cytoplasm in peripheral layer are called