What is the only vein that carries high oxygenated blood?

The pulmonary vein is unique among veins because it is responsible for carrying highly oxygenated blood from the lungs to the heart. In the respiratory process, blood picks up oxygen in the lungs and is then transported back to the heart through the pulmonary veins. This is contrary to the typical function of veins, which carry deoxygenated blood back to the heart.

The coronary vein and the femoral vein, on the other hand, transport deoxygenated blood. The coronary veins drain blood from the heart muscle itself, while the femoral vein carries blood from the lower extremities back to the heart. The aorta, while it carries oxygen-rich blood, is an artery, not a vein. It transports blood away from the heart to various parts of the body. Thus, the pulmonary vein stands out as the sole vein that carries high oxygenated blood, making it the correct answer.