The wall of the pollen tube is made up of:

One pollen mother cell may produce four germinating pollen grains,each with two male nuclei and one tube nucleus. How many meiotic divisions are necessary to bring this about?

Given below are two statements: One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A) :$ Cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.
Reason $(R):$ Presence of more than one nucleus in the tapetum increases the efficiency of nourishing the developing microspore mother cells.
In light of the above statements,choose the most appropriate answer from the options given below:

How many theca are present in each lobe of a typical bilobed angiosperm anther?

Which element is required for the germination of pollen grains?

Sporopollenin,a chemical substance,is found in . . . . . .