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
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To entertain and develop inspiration and curiosity in people
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bacteria, illness, poison, ect.
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