The directional movement of plant part in response to light
Aur koi.???
Movement or growths in response to light is called phototropism

Chemotroprism…
Geortropism is the movement of plant dueto the gravity
Responses of organism to gravity is geotropism
Now geotropism.
Stem tip grows in the direction of light is called phototropism
Phototropism is the ability of a plant, or other photosynthesizing organism, to grow directionally in response to a light source.
Growth of plant toward light
The phototropism is the movement of plant part during the light

the orientation of a plant or other organism in response to light, either towards the source of light ( positive phototropism ) or away from it ( negative phototropism ).