In angiosperms,male gametes are formed from

Identify the structures marked $A$ to $F$ in the given diagram.

Where is the food stored in a pollen grain?

Given below are two statements.
Statement $I$: Generally,anthers in angiosperms are dithecous,having two pollen sacs in each lobe.
Statement $II$: Each sporangium produces pollens from sporogenous tissues by the process of sporogenesis.
In light of the above statements,select the correct answer from the options given below.

How many meiotic divisions are necessary to produce $100$ pollen grains?

What is the full form of $MMC$?