At its core, circulation is how blood gains and loses oxygen as it moves through the body. Veins carry oxygen-poor blood from the body to the right side of the heart. The heart pumps this blood through the pulmonary arteries into the lungs. The blood picks up oxygen in the lungs and moves into the left side of the heart. The heart pumps the oxygen-rich blood through the aorta, the body’s main artery. The blood moves through arteries and capillaries to deliver oxygen and nutrients to cells all over the body. Then the newly oxygen-poor blood is carried through the veins to the right side of the heart, and the cycle of circulation begins again.
Which of these is a difference between veins and arteries?
A
Arteries carry blood, and veins do not.
B
Veins carry oxygen, and arteries do not.
C
Arteries flow toward the heart, and veins flow away from the heart.
D
Veins flow toward the heart, and arteries flow away from the heart.
C
Arteries flow toward the heart, and veins flow away from the heart.