Which endocrine structure is formed after ovulation?

Which of the following represents a condition where the motility of the sperms is highly reduced?

Which hormone is responsible for ovulation?

The human sperms were first seen and discovered by

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

Identify the follicle showing the presence of an antrum in the given diagram.