_Fats and various C <---------------------------+ compounds_ | | | | | v | _Decomposition | bacteria_ | | | | | v | _Various | C | compounds | eventually ^ to_ | | | | | v | _CO₂ <---------------+ | in | | the air_<-+ | | | | | | | | _Plant respiration_ | v | | | _Green | | | plants_---+ | | | | | | | | v | | _Carbohydrates, | | fats and | | other C compounds_ | | | | | | | | v | | _Animals_---->_Animal respiration_ | | | | | +---->----------------------------+ FIG. 69.--Diagram to illustrate the circulation of carbon through the agency of bacteria.] [Illustration: