Answer:
The lungs oxygenate blood, arteries simply carry oxygenated blood. But there is one exception to this rule. Arteries carry oxygenated blood in systemic circulation (blood circulation to the entire body excluding the lungs). In pulmonary circulation (blood circulation to the lungs), the pulmonary artery carries deoxygenated blood from the heart to the lungs where it gets O2 and it transported back to the heart by the pulmonary vein.