Question

How do auxins promote the growth of tendril around a support.....
(pls answer tomorrow is my test)

Answer 1

Auxin is plant hormone which is synthesized at the tip of the shoot. It helps the cell grow longer. When atendril comes in contact with a support, auxin stimulates fastergrowth of the cells on the opposite side that's why the tendril forms a coilaround the support.

Answer 2

When the tip of a tendril touches a support , then the auxins present in its tip move to that side of tip which is away from the support . Auxins promote growth . So due to more auxins in it , the side of tendril away from the support grows faster than the side which is in contact with the support and makes the tendril twirl around the support .