Which best defines homeostasis? modifying the external environment maintaining a stable internal environment controlling what enters and exits the cell movement of materials into the cell

B. maintaining a stable internal environment

Explanation:

Took the test :)

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.