Organisms in an ecosystem require oxygen to carry out cellular respiration. How is the oxygen level in an ecosystem maintained?


OA. Most organic matter consists of oxygen, which is released when

the matter is broken down by decomposers.

BOxygen is released by autotrophs that carry out photosynthesis.

C. Oxygen is released by heterotrophs that carry out cellular

respiration.

OD. Most biomass consists of oxygen, which is released when the

biomass is burned.