Answer:
The answer is A) energy.
Explanation:
Mitochondria are cellular organelles and are the energy factories of cells, since they are responsible for supplying most of the energy necessary for cellular activity. Mitochondria act as power plants of the cell and synthesize ATP at the expense of metabolic fuels. All living cells have mitochondria but some cells have more mitochondria than others. Muscle cells have many mitochondria, since they store a lot of energy.
