The answer is breathing. This is what I got from my homework paragraph. In breathing, oxygen and carbon dioxide are exchanged with the external environment but there is not a gain of energy and a chemical reaction does not occur.
The exchange of gases between animals and the environment is a mechanical process which contains the exhalation and inhalation of gases from the environment and this process is known as breathing.
While cellular respiration is the breakdown of glucose for the energy production at cellular level.
Evaporation is the conversion of liquid into vapors and transpiration is the evaporation of liquid fro the surface of leave.
