Which of the following is an enzyme-resistant substance?

What is the intine of a pollen grain made of?

In angiosperms,male gametes are formed from

Which of the following is surrounded by a carbohydrate-rich wall?

Which of the following is not a character of a typical anther?

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.