Match the following columns:

Column-$I$ (Pre-fertilization)	Column-$II$ (Post-fertilization)
$P$. Ovule	$I$. Fruit
$Q$. Integument	$II$. Embryo
$R$. Ovary	$III$. Seed
$S$. Ovary wall	$IV$. Pericarp
$T$. Zygote	$V$. Seed coat

Which of the following structures degenerate after fertilization in angiosperms?

Select the correct option from the following statements regarding pollen grains:
$I -$ Pollen grains are rich in nutrients.
$II -$ In recent years,pollen tablets have been used as food supplements.
$III -$ In western countries,a large number of pollen products are available in the market in the form of tablets and syrups.
$IV -$ Pollen consumption has been claimed to increase the performance of athletes and racehorses.
$V -$ Pollen grains can germinate on the stigma after losing their viability.

External fertilization is mostly observed in organisms that.....

Bisexual flowers which never open are known as:

List the changes observed in an angiosperm flower subsequent to pollination and fertilisation.