Pollen grains are released from

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.

How many pollen sacs (microsporangia) does each lobe of an anther contain?

Which is the outermost layer of the anther wall?

$A$ plant that develops directly from a pollen grain is called ....

In angiosperms,male gametes are formed from