The difference between an artery and a vein is that arteries are larger, more muscular and more elastic than veins; they carry blood that is under pressure from having been pumped out of the heart; veins are under much less pressure, so they are not as strong
NADP is the most abundant acceptor for hydrogen released in the Krebs cycle.
All of them. Air because in helps make food it also lets the plant breath. Water because it helps move nutrients into the plant. Soil because plants can’t grow without soil.