This makes their blood pressure double the amount of most mammals! In the upper portion of their necks there is a complex pressure regulatation system that maintains blood flow when the giraffe bends down to drink.In their brain there are elastic blood vessels that connect to one way valves in the neck to prevent the head from swellin when they bend over.his makes their blood pressure double the amount of most mammals! In the upper portion of their necks there is a complex pressure regulatation system that maintains blood flow when the giraffe bends down to drink.
A plant hormone that promotes root formation and bud growth.An auxin is a growth regulating substance that can be found in the meristems of plants. The concentration of auxin has the deciding effect on how much (and where) growth occurs in a plant.
Auxins were the first of the major plant hormones to be discovered. They derive their name from the Greek word Î±ÏÎ¾ÎµÎ¹Î½ (auxein - to grow/increase). Auxin (namely IAA) is present in all parts of a plant, although in very different concentrations.uxins and their role in plant growth were first described by the Dutch scientist Frits Warmolt Went. Kenneth V. Thimann isolated this phytohormone and determined its chemical structure as indole-3-acetic acid (IAA). Went and Thimann co-authored a book on plant hormones, Phytohormones, in 1937.