Side chains of amino acids are are:
A. all nonpolar
B. non-polar if they contain N or S
C. all polar
D. may be polar or nonpolar
E. none of the above choices is correct

this is math not biology xd

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.