2.79-2.81

Stimuli = changes in the environment (temperature, light etc.)
-The plant has receptors which can detect the stimuli.
-The response takes the form of growth
                  This type of response is called a tropism
1) Photo tropism
- This is the growth response due to light (the plant grows towards the light)
- Auxin is a hormone which causes more growth on the side of the plant which causes bending
2). Geotropism
-This is the growth response due to gravity
-        Positive Geotropism= the embryonic root grows down into the ground
         Negative Geotropism= the embryonic shoot grows upwards

-To prove this, if you turn the seed sideways the shoot will still grow upwards and the root downwards