In flowering plants,a mature 'male gametophyte' is derived from a 'pollen mother cell' by

The microsporophyll of an angiosperm is known as.......

Which of the following is true regarding the wall layers of the anther?

In wheat and rice, how long does the pollen grain remain viable after being released?

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.

Majority of pollen grains are shed at