7. Blood enters the right atrium of the heart from the (A) aorta (B) left ventricle (C)pulmonary vein (D) vena cava

## Step 1<br />The heart is a vital organ in the human body that pumps blood throughout the body. It has four chambers: the right atrium, the right ventricle, the left atrium, and the left ventricle.<br />## Step 2<br />Blood enters the right atrium of the heart from the vena cava. The vena cava is the largest vein in the body and it carries deoxygenated blood from the body back to the heart.<br />## Step 3<br />The aorta, left ventricle, and pulmonary vein do not directly deliver blood to the right atrium. The aorta is the main and largest artery in the human body, carrying oxygenated blood from the left ventricle to the rest of the body. The left ventricle is one of the four chambers of the heart, which pumps oxygenated blood to the aorta. The pulmonary vein carries oxygenated blood from the lungs to the left atrium.