In human females,meiosis-$II$ is not completed until $..........$.

For ovulation,what is required for the reflex action of the ovum?

What is the number of primary follicles left in each ovary at puberty?

When is the second polar body extruded from the oocyte nucleus?

When released from the ovary, a human egg contains:

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