How many half lives will have passed if 7500 atoms of carbon-14 remain? How old would the rock be? ANSWER QUICK PLSS (the topic is actually integrated science but they didn't have that option :/)

55

Explanation:

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.