Correct Answer: Red blood cellsThe job of the circulatory system is to provide oxygen and nutrients to all the parts of the body. Waste products like carbon dioxide are carried away so they can leave the body.The circulatory system includes the heart, blood, and blood vessels. Blood vessels are the tubes that carry blood all over the body. Arteries, veins, and capillaries are all different kinds of blood vessels. It also includes the lymphatic system, which comprises a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally towards the heart.