What are prions?
a) mobile segments of dna
b) tiny molecules of rna that infect plants
c) viral dna that has had to attach itself to the host genome
d) misfolded versions of normal brain protein
e) viruses that invade bacteria

b is the best answer for this question.

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.