True.
In aerobic respiration , there is complete oxidation of carbohydrates in the presence of oxygen producing carbon dioxide, water and energy in the form of Adenosine Triphosphate(ATP)
And in anaerobic respiration, substances are broken in complete absence of oxygen, thus, there is incomplete degradation of glucose with the release of C02, other organic compounds and energy
Therefore, the release of CO2 in the air, helps the plants to undergo photosynthesis to make food