Which cells in the mammalian testis provide nutrition to the developing spermatozoa?

The mother germ cells are transformed into a mature follicle through a series of steps. Provide the missing steps in the blank boxes.
$\boxed{\text{Oogonia}} \to \boxed{A} \to \boxed{\text{Primary follicle}} \to \boxed{B} \to \boxed{C} \to \boxed{\text{Mature or Graafian follicle}}$

Ovulation in mammals is caused by

How many spermatozoa are formed from one secondary spermatocyte?

If $2n = 16$ in a primary spermatocyte which is in the metaphase of the first meiotic division,what shall be the total number of chromatids in each of the secondary spermatocytes?

In humans,what is the ratio of the number of gametes produced from one male primary sex cell to the number of gametes produced from one female primary sex cell?