How is the atmospheric oxygen that is taken in by living things for respiration replaced?
A) After living things use oxygen for respiration, they exhale the oxygen back to the atmosphere.
B) Photosynthesis uses the carbon dioxide that is exhaled by living things to make oxygen.
C) Weathering releases oxygen that is locked in rocks due to sedimentation.
D) Oxygen that is dissolved in water such as oceans is released.
