Release of sperm from the seminiferous tubules is called

The formation of polar bodies occurs during the formation of which of the following?

At which stage of spermatogenesis does the sperm acquire a mature structure with a nucleus and other organelles?

Which cells provide nutrition to the developing spermatozoa during spermatogenesis?

The schematic representation of spermatogenesis is given below. How many chromosomes do $P$,$Q$,and $R$ contain?
$P$ (Spermatogonia) $\rightarrow$ $Q$ (Primary Spermatocyte) $\rightarrow$ $R$ (Spermatid)

Which part of the given diagram contains enzymes necessary for fertilization?