In a pollen grain,the smaller cell with dense cytoplasm and a spindle-shaped nucleus is called the ....

Complete the following flow chart:
Pollen Mother cell $\to$ Pollen tetrad $\to$ Pollen grain $\to$ Vegetative cell
Pollen Mother cell $\to$ Pollen tetrad $\to$ Pollen grain $\to$ ..........

In over $60\%$ of angiosperms,pollen grains are shed at which of the following stages?

Generally,how many middle layers are formed in the wall of the anther lobes?

When a pollen grain is shed at the $3$-celled stage,name the cells it contains.

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: