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.