I think it should be A, not 100% sure tho
<em><u>Answer:</u></em>
They generate chemical energy in the form of ATP.
<u><em>Explanation:</em></u>
Mitochondria are the powerhouses of the cell because they "burn" or break the chemical bonds of glucose to release energy to do work in a cell. This releases energy (ATP) for the cell. The more active a cell (such as a muscle cell), the more mitochondria it will have.