Critical thinking is a way of looking at a problem and ultimately arriving at a decision

The cardiac muscle receives its supply of oxygenated blood by which of the following mechanisms?

A) Absorption of oxygen from the blood returning from the lungs B) Coronary arteries that branch off the aorta C) Coronary veins that branch off the pulmonary vein as it returns oxygenated blood to the heart D) None of the above

According to the CDC, which factor contributes most to premature death in the U.S. population?

a. Lifestyle and behaviors b. Lack of medical care c. Social and environmental factors d. Genetic makeup