Split reins are a piece of equipment used for communicating with a horse while it is being ridden. Split reins are actually two separate, individual reins that are used together, with one rein on each side of the horse's neck.
As discussed above, mitochondria are the sites of respiration, and generate chemical energy in the form of ATP by metabolizing sugars, fats, and other chemical fuels with the assistance of molecular oxygen.
A: Mitochondria are the membrane-bound structures that produce energy for cells. The mitochondria are thought to be descended from a once free-living cell that set up a symbiotic relationship with a host cell. Mitochondria are organelles, membrane-bound structures that perform specific functions within a cell.