What do veins carry?

Veins are responsible for carrying blood towards the heart. This is a critical function in the circulatory system, as veins collect deoxygenated blood from various parts of the body and transport it back to the heart for reoxygenation in the lungs.

In general, the heart pumps oxygenated blood out through the arteries to deliver oxygen and nutrients to the tissues, while veins perform the vital task of returning blood to the heart. This understanding of blood flow is essential for anyone working in a health-related field, as it lays the foundation for comprehending how bodily functions and treatments can be affected by blood circulation dynamics.

The other choices relate to aspects of blood transport and functions but do not accurately describe the role of veins specifically. For instance, arteries are the vessels that carry blood away from the heart, and both oxygen and nutrients are primarily haulered in the arterial system to the tissues, rather than being the specific role of veins. Thus, the focus on veins returning blood to the heart is critical for an understanding of the circulatory system.