Answer: An artery carries blood away from the heart; a vein carries blood to the heart.
Explanation: Veins carry blood towards the heart. This blood has given most of its oxygen to the body, so it is low on oxygen and high in carbon dioxide. It enters the right side of the heart and travels to the lungs. There, the lungs eliminate carbon dioxide and exchange it for more oxygen. The oxygen-rich blood enters the left side of the heart. Then, arteries carry blood away from the heart. Pulmonary circulation brings blood from the heart to the lungs and back. Systemic circulation brings blood from the heart to the rest of the body and back.
The difference between an artery and a vein is that arteries are larger, more muscular and more elastic than veins; they carry blood that is under pressure from having been pumped out of the heart; veins are under much less pressure, so they are not as strong
