In which family is a monothecous anther found?

Tapetal cells are characterized by

An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is

Majority of pollen grains are shed at

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.

$A$ microspore mother cell forms