The living organisms must not reach equilibrium in the concentration of oxygen and carbon dioxide so that the Exchange of gases continues . Otherwise respiration and photosynthesis will stop.
Explanation:
Gases move along the concentration gradient i.e. from their higher concentration to lower concetration.
If living organisms reach a equilibrium of carbon dioxide and oxygen concentration, then The gases will not move in and out of the cells.
This is because at state of equilibrium the concentration of gases on both side become equal and the movement completely ceases.
If gaseous exchange in the body stops the process of respiration and photosynthesis in Plants and respiration in animal will completely stop.
