Which organic substance can withstand extreme environmental conditions and cannot be degraded by any known enzyme?

How many lobes are present in a mature anther?

If there are four microspore mother cells in an anther,what will be the total number of pollen grains produced?

Which is an incorrect statement?
$I$. Each cell of sporogenous tissue in anther is capable of giving rise to a microspore tetrad.
$II$. The pollen grain represents the male gametophyte.
$III$. Pollen grains are usually triangular and $10-15 \mu m$ in diameter.
$IV$. Sporopollenin is one of the most resistant organic materials,which can be destroyed only by strong acids and alkalis.

Identify the incorrect statement regarding sporopollenin.

In monocots,the male gametophyte is represented by: