👉 Need explain veins in one sentence.Veins are blood vessels that carry deoxygenated blood back toward the heart, using valves to prevent backflow and relying on muscle contractions and gravity to help propel the blood upward.
👉 Need explain veins in one sentence.Veins are blood vessels that carry deoxygenated blood back toward the heart, using valves to prevent backflow and relying on muscle contractions and gravity to help propel the blood upward.
