Ventricles are the two lower chambers that receive blood from the atria and force blood into arteries.

Ventricles are the two lower chambers that receive blood from the atria and force blood into arteries.

• A. The heart's valves
• B. The walls dividing left and right sides
• C. The atrial appendages
• D. Two lower chambers that receive blood from the atria and force blood into arteries

Answer: (D)

Ventricles are the two lower chambers of the heart that receive blood from the atria and force it into the arteries. This defines their essential role as the pumping chambers: the right ventricle pushes blood to the lungs via the pulmonary artery, while the left ventricle pushes blood to the rest of the body via the aorta. The other phrases describe structures that are not chambers—heart valves regulate flow, the walls between the left and right sides are the septa, and the atrial appendages are extensions of the atria. So the described function—two lower chambers that receive blood from the atria and propel it into the arteries—precisely matches the ventricles.

Ventricles are the two lower chambers of the heart that receive blood from the atria and force it into the arteries. This defines their essential role as the pumping chambers: the right ventricle pushes blood to the lungs via the pulmonary artery, while the left ventricle pushes blood to the rest of the body via the aorta. The other phrases describe structures that are not chambers—heart valves regulate flow, the walls between the left and right sides are the septa, and the atrial appendages are extensions of the atria. So the described function—two lower chambers that receive blood from the atria and propel it into the arteries—precisely matches the ventricles.