STD 12 - 8. microbes in human welfare — BIOLOGY STD 12 Science — Question

$I$. Each cell of sporogenous tissue in anther is capable of giving rise to microspore tetrad.
$II$. The pollen grain represent male gametophyte.
$III$. Pollen grains are usually triangular and $10-15 \mu m$ in diameter.
$IV$. Sporopollenin is one of the most resistance organic material which can be destroyed only by strong acids
and alkali.

$A$ - number of chromosomes in endosperm

$B$ - number of chromosomes in egg cell

$C$ - number of chromosomes in polar nuclei