Question

The bending of the stem of a plant towards a source of light is caused by the action of a phytohormone known as (a) abscisic acid
(b) auxin
(c) gibberellins
(d) cytokinin

Answer 1

Answer:

(b) auxin

Explanation:

When a plant senses a directional light stimulus it redistributes its auxin molecules to the side that is further away from the light. As a consequence, the plant cells that are further away from the light experience a greater auxin concentration and grow faster, causing the shoot to bend towards the light.