Question

.State how concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light ?​

Answer 1

When light falls on the side of the shoot auxin diffuses towards the shady side of the shoot. This concentration of the auxin stimulates the cell to grow longer on the side of the shoot which is away from light. Thus plant appears to bend towards light.

Answer 2

concentration always travels from higher concentration to lower concentration which means it travels lower concentration to higher concentration