<span>Cells responsible of making energy and performing respiration within the cell. Depending on what type of organism they are found at, they can be known as Mitochondria, if they are in animals; and if they are in plants, Chloroplasts.
Mitochondria create energy for the cell by breaking down sugars, fats, and other fuels consumed by the cell.
Chloroplasts, on the other hand, since they are found at plants, convert sunlight into energy.</span>
Doctors would let your body's immune system fight off a bacterial infection. If the infection gets worse, then the doctors would proscribe you with some antibiotics so it'll fight off the harmful bacteria.
Im pretty sure that it is (A) because blood pumps to get every where through your body. If it didn't one half of your body would feel cold or numb.