In $Agave$ (Century plant),vegetative propagation occurs through which of the following?

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.

Which of the following pairs of plant parts are both haploid?

What is gamete transfer? State its necessity.

In castor and maize plants, . . . . . .

The life cycle of an angiosperm is given below. What are $P, Q$ and $R$?
$P \quad Q \quad R$