Birds and Mammals Are Endotherms,meaning They Spend Enormous Amounts of Energy

Birds and mammals are endotherms,meaning they spend enormous amounts of energy maintaining a constant body temperature.To meet these energy needs,birds and mammals independently evolved four-chambered hearts,completing the separation of oxygen-rich from oxygen-depleted blood.How would this maximize the amount of oxygen reaching tissues?

A) Diffusion of oxygen from oxygenated blood into tissues would be increased.
B) Diffusion of oxygen from oxygenated blood into tissues would be decreased.
C) Less energy would be required to pump oxygen into the blood.
D) Less energy would be required to pump oxygen into the tissues.
E) Less energy would be required to pump oxygen into the lungs.