Which type o go economic system do you think has been the most effective in promoting economic growth

Located throughout the body, veins return deoxygenated blood to the heart. Veins have valves to prevent backflow of blood and larger lumens (internal spaces) than arteries. The vein lumen has a smooth endothelium, or inner lining. The endothelium is part of the tunica intima, the innermost layer of the vein wall