What is the role of veins in the circulatory system?

Veins play a crucial role in the circulatory system by transporting deoxygenated blood back to the heart. After blood delivers oxygen and nutrients to tissues throughout the body, it returns through the veins, which have thinner walls compared to arteries and often have valves to prevent backflow. This mechanism is essential for maintaining blood circulation and ensuring that the heart can pump blood efficiently to the lungs for re-oxygenation.

While arteries carry oxygenated blood away from the heart, veins are specifically tasked with bringing blood back, making their function vital in the overall process of circulation. Other options do describe functions related to the circulatory system but do not accurately represent the primary role of veins in blood transport.