Which statement about cellular respiration is true?
a. it produces oxygen.
b. it requires water.
c. it is used by every living cell.
d. it converts energy to food.

Cellular respiration is the process of breaking down food such as glucose into carbon dioxide and oxygen. During the process, cellular respiration also releases energy in the form of ATP (adenosine triphosphate) for use by all energy consuming activities of the cell. It is found in the simultaneous process of Gycolysis and Kreb’s cycle. Glycolysis is the breakdown of glucose to two pyruvic acids. These two pyruvic acids will be used for the production of carbon dioxide and water in Kreb’s cycle. The answer is letter A.