The breakage of the membrane surrounding the acrosome in a mammalian sperm is known as:

Which of the following statements is correct regarding the human sperm?

Ejaculation of human male contains about $200 - 300$ million sperms,of which for normal fertility . . . . . . $\%$ sperms must have normal shape and size and at least . . . . . . $\%$ must show energetic motility.

At the time of birth,in which form are the oocytes present?

Arrange the following cell layers/structures around the female gamete, from outer to inner side :
$A$. Zona pellucida
$B$. Perivitelline space
$C$. Corona radiata
$D$. Plasma membrane of ovum

In humans,what do the male germ cells differentiate into after the completion of the first meiotic division?