The cardiac muscle receives its supply of oxygenated blood by which of the following mechanisms?
a.Coronary arteries that branch off the aorta
b.Coronary veins that branch off the pulmonary vein as it returns oxygenated blood to the heart
c.Absorption of oxygen from the blood returning from the lungs
d.None of the above
Answer: a. Coronary arteries that branch off the aorta