(A) What is tropism ?
(B) How do ausinx promote the growth of a tendril around a support?
a) Tropism is a phenomenon which shows the growth and directional movement of plants, in response to an environmental stimulus.
b) Ausinx promote the growth of a tendril as it is a plant hormone that is integrated at the tip of the shoot as it helps the cell to grow longer. Whenever a tendril comes in contact with a support, auxin arouses faster growth of the cells on the opposite side that's why the tendril forms a coil around the support that can be pole, rod or anything.