Mesophiles are group of bacteria that grow best in such conditions.
It just depends what you are studing:
I believe the answer you are looking for is they are all body systems found in the human body, or organ systems.
The answer you are looking for is C. Nitrogen. Commonly found as Nitrite
(N3) or Nitrate (N2) nitrogen is a key element required by all life. Nitrogen is most often released back into the atmosphere by micro-organisms during the decomposition of organic matter, and into the ground through decomposition and defecation (Pooping).
