Question

A vine growing around a lamp post is an example of

Answer 1

This is an example of phototropism. The vine, by growing around a lamp post is searching for more light, whether coming from the lamp when is on, or the sun, growing in its direction. Phototropism is the characteristic of something to respond to light stimulus.

Answer 2

A vine growing around a lamp post is an example of PHOTOTROPISM. 
Phototropism refers to the movement of a plant in response to light. The plant may be moving towards the light, in which case it is describe as positive phototropism; the plant may also be moving away from the light source, in which case it is describe as negative phototropism.
The plant in the question above is exhibiting positive phototropism because it is moving toward the source of light.<span />