Hint: The estrus cycle also called an oestrous cycle, is the set of physiological changes which are induced by reproductive hormones in female mammalians. The oestrous cycle can be divided into four main stages. They can be named as proestrus, estrus, metestrus and diestrus.
Let’s discuss the options and find out the correct answer.
-Proestrus is the developing stage. As the ovarian follicle enlarges, it starts secreting estrogen which is essential for the preparation of estrus and pregnancy. Estrus is the stage where ovulation takes place. This stage is also known as the period of heat and the female is sexually open and can receive the male gametes. It is also controlled by estrogen. Metestrus is the stage where the formation of corpus luteum takes place due to the influence of decreasing estrogen and increasing progesterone levels. Diestrus is the stage when corpus luteum starts functioning and an increase in the levels of progesterone is seen. Hence, option A is correct.
-Estrogen are the hormones that are important for the sexual and reproductive cycle, especially in women. They are sometimes referred as the female sex hormones. Estrogen controls the menstrual cycle and affects the female body in various ways too.
-The main sex hormone and anabolic steroid in males is known as testosterone. It plays an important function in the growth of male reproductive tissues as well as developing secondary sexual characteristics.
Hence, option A: Progesterone is the correct answer.
Note: Progesterone inhibits the production of follicle stimulating hormone (FSH) and luteinizing hormone(LH). After the maturity of female sex hormones and is interrupted by the pregnancy or anestrus phases. They continue until death. One or more estrus cycles can take place during the breeding season of species.