I believe, for the artery, they have, an open, circular lumen an a thick media
Veins on the other hand, have somewhat collapsed lumen and a thinner media. Arteries are blood vessels that carry blood out of the heart to other parts of the body, all arteries carry oxygenated blood except the pulmonary artery which carries deoxygenated blood from the heart to the lungs. Veins carry blood from other body parts to the heart, all veins carry deoxygenated blood except the pulmonary vein which caries oxygenated blood from the lungs to the heart.
Answer:
Well...
Explanation:First of all skin color is determined by how much melanin you have and the one thing that would show more variability in the human population is probably the one that uses less genes, because of how we come from only two genes which makes us different.
Because though there is a lot of available water, an ever shrinking 3% is freshwater, which comes from groundwater and streams. The ocean is salinated and in order for it to be fit to be used by humans for domestic needs or for drinking, it needs to undergo a huge desalination process which costs lots of money and time.
