What is the function of veins in the circulatory system?

Veins are a crucial component of the circulatory system, primarily responsible for transporting blood back to the heart. The correct choice highlights that veins carry blood at low pressure and contain valves.

Veins typically handle deoxygenated blood, which returns from the body to the heart. The low-pressure system within the veins is important because it allows for efficient blood return without requiring the same pressure as arteries. Valves in the veins prevent backflow, ensuring that blood moves toward the heart despite the lower pressure. This mechanism is particularly vital in areas like the legs, where blood must travel against gravity to return to the heart.

While other choices mention functions like carrying blood at high pressure or transporting nutrients, those roles are associated with arteries and the digestive system, respectively, illustrating a distinct difference in function and mechanics within the circulatory system.