What do the carbon, oxygen, and nitrogen cycles all have in common?
a. they all include an exchange of gases with the atmosphere.
b. none of the cycles are biogeochemical cycles.
c. they are all byproducts of photosynthesis.
d. they all sustain life, but living organisms have no part in the cycle.

Answer;

A. They all include an exchange of gases with the atmosphere.

Explanation;

The carbon, oxygen, and nitrogen cycles are all biogeochemical cycles meaning that the chemicals spend a portion of the cycle in living things (hence the bio) and a portion in the nonliving environment (geo).  They show the movement of elements through living and nonliving components of the Earth.

Additionally, they recycle nutrients that are essential to all organisms. In all the cycles the atmosphere is a major reservoir and involve plants as transformers of the nutrients.

is in the form atp or adenosine triphosphate

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.