Menstrual cycle is controlled by

In girl, the first menstruation begins at puberty and is called .....

Arrange the events of menstrual cycle as they occur

$I.$ Secretion of $FSH$

$II.$ Growth of corpus luteum

$III.$ Growth of follicle and oogenesis

$IV.$Ovulation

$V.$ Sudden increase in level of $LH$

Ovulation in the human female normally takes place during the menstrual cycle

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.

Assertion $A$: Endometrium is necessary for implantation of blastocyst.

Reason $R$: In the absence of fertilization, the corpus luteum degenerates that causes disintegration of endometrium.

In the light of the above statements, choose the correct answer from the options given below:

The structure formed after release of ova from graafian follicles and secretory in nature, is