Which of the following events are a part of a menstrual cycle?
i. The pituitary gland stimulates ovaries to produce estrogen and progesterone.
ii. Ovulation takes place.
iii. Estrogen stimulates the uterus to build up extra tissue and blood layer to make the wall nutritious for a zygote.
iv. In the absence of fertilisation, the egg is eliminated from the body along with the uterus lining which comes out as blood discharge at the time of menstruation.
i, ii, iii and iv
The ovaries in females release one egg alternately every month which is stimulated by the release of estrogen and progesterone from the pituitary gland. The estrogen also builds up a lining of blood in the inner wall of the uterus which prepares the uterus for pregnancy. In case of absence of fertilization, the body gets rid of the egg along with the inner lining of the uterus which comes out as menstrual blood. The cycle occurs once in every 28-30 days.