Which change in the earth's atmosphere allowed organisms to live on land? A) a collision with a comet
B) the development of the ozone layer
C) a strong burst of particles from the sun
D) the absorption of carbon dioxide by oceans

Explanation:

hi it's my first answer lol btw the answer is

D :)

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.