The process of formation of microspores from a pollen mother cell is called

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.

Even after killing the generative cell with a laser beam,the pollen grain of a flowering plant germinates and produces a normal pollen tube because:

Which of the following is an enzyme-resistant substance?

Majority of pollen grains are shed at

How many microsporangia are located at the corners of a typical bilobed anther of angiosperm?