38. A. Oxygen: carbon dioxide
39. The correct response is B. All living things must carry out cellular respiration to release the chemical energy stored in the bonds in food molecules. One such important molecule is glucose. As glucose is broken down during anerobic respiration, as in yeast cells, 2 A.T.P. are yielded provide the energy for its life processes. In aerobic organisms, such as plants and animals, 36 A.T.P. are the net result. It is the A.T.P. which supplies our cells with the energy for metabolic processes.
40. D. Fermentation.
