Human Reproduction — BIOLOGY STD 12 Science — Question

2. Luteal

Explanation:

Menstrual cycle occurs in three major phases namely menstrual phase, proliferative phase and secretory phase. 

Proliferative phase is regulated by the hormones secreted by anterior pituitary gland whose secretion stimulates the ovarian follicle to secrete oestrogen.

During the second week, most of the developing follicles die and one follicle continues to grow and gets mature to form Graafian follicle.

This follicle undergoes ovulation on 14th day of the cycle.

Secretory phase is marked by the presence of corpus luteum (yellow body). This phase is also called luteal phase. 

In the presence of pregnancy this yellow body secretes human chorionic Gonadotropin (hCG) and in the absence of pregnancy, it regresses to form corpus albicans and menstruation starts (menstrual phase).

Since, ovulation occurs in Luteal phase, fertilisation can occur in Luteal phase.