The blood veins is

a. leaving the lungs.

b. moving in a single file

c. traveling to the heart.

These are blood vessels that take oxygen-poor blood back to the heart. Veins become larger and larger as they get closer to the heart. The superior vena cava is the large vein that brings blood from the head and arms to the heart, and the inferior vena cava brings blood from the abdomen and legs into the heart.

C.-.

Arteries are blood vessels responsible for carrying oxygen-rich blood away from the heart to the body. Veins are blood vessels that carry blood low in oxygen from the body back to the heart for reoxygenation. SO ... C