After you finish a big meal, the level of glucose in your bloodstream increases. what happens next in order for your body to process the glucose? when glucose reaches a certain level, your hypothalamus stops producing it. your stomach releases ghrelin to counteract the glucose. your pancreas produces insulin to manage the glucose. your fat cells release leptin, which tells your hypothalamus to stop producing glucose.

the answer to your question is:

c. complementary base-pairing

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.