Answer:
Soil getting dug up by moles.
A stands out most to me, CO comes from the air and air is basically oxygen we breath. When we exhale CO comes out (of course). I would say A is correct.
Answer:
pulmonary circulation
Explanation:
The pulmonary circulation moves the blood between the lungs and heart. Since the blood carries oxygen the heart pumps it to every body part including the lungs so we can maintain homeostasis.
Answer:
Radiometric dating for the analysis of isotopes in the fossil.
Explanation:
Radiometric dating can be used to determine the precise age of a fossil by measuring isotoped decay within tge fossil or the surrounding rock in contact with it.