Blood from the body enters the right atrium via the:

• A. Vena Cava
• B. Pulmonary Veins
• C. Aorta
• D. Pulmonary Artery

Answer: (A)

Systemic venous return from the body enters the heart through the superior and inferior venae cavae, delivering deoxygenated blood directly into the right atrium. From the right atrium, blood moves to the right ventricle and then to the lungs for oxygenation. The other vessels have different roles: pulmonary veins return oxygenated blood from the lungs to the left atrium; the aorta carries oxygen-rich blood from the left ventricle to the body; the pulmonary artery carries blood from the right ventricle to the lungs.