Identify the stage.

Explanation

(a) Ovulation occurs in response to surge of LH secretion. LH convets ruptured empty follicle into corpus luteum.
(b) Corpus luteum secretes progesterone which is essential for preventing ovulation, reducing uterine contractions, maintaining pregnancy, development of placenta and secretory activity of endometrium, and development of breasts.
( c) Placenta secretes a number of hormones out of which hCG (human chorionic gonadotropin) is required for maintaining pregnancy (through progesterone) and growth of foetus.
(d) The fully developed foetus and placenta produce foetal ejection reflex which stimulates secretion of oxytocin from posterior pituitary under positive feedback response. Higher concentration of oxytocin causes strong uterine contractions which lead to parturition.