On the fourteenth day of the menstrual cycle,the female gamete released is . . . . . . .

Sertoli cells are found in the testis. What are these cells called?

How many secondary spermatocytes are required to form $400\,million$ spermatozoa?

An antrum is the characteristic of $...$ follicles.

Arrange in the correct sequence the structures formed during spermatogenesis:
$(a)$ Spermatogonia
$(b)$ Secondary spermatocyte
$(c)$ Primary spermatocyte
$(d)$ Spermatid

Match the part of the sperm in Column $I$ with its component in Column $II$ and its function in Column $III$, and select the correct option.

Column $I$ (Part of sperm)	Column $II$ (Component) and Column $III$ (Function)
$A$. Head	$Q$. Acrosome - $Z$. Secretes penetrating enzyme
$B$. Neck	$P$. Centrioles - $X$. Helps in formation of synkaryon spindle
$C$. Middle piece	$R$. Nebenkern - $Y$. Provides energy for sperm movement
$D$. Tail	$S$. Axial filament - $W$. Whiplash movement in female reproductive tract