Which one of the following statements is not true?

Differentiate between Stamen and Pistil.

The advantage of cleistogamy is

Choose the odd one with respect to the flowering and fruiting pattern.

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.

Identify the incorrect statement.