The air we breathe is mostly a mixture of oxygen and nitrogen. How do air molecules change when they reach altitudes above 100 km? I need to make sure the answer I have is right.

maritime tropical may be your answer.

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.