Gravitropism is a growth response by part of a plant to gravity.
a.[2]
Name one other tropism. Give the stimulus the plant responds to in the tropism you have named.
b.[6]
Plan an investigation to show the effect of gravity on the growth of plant roots.
Include details of any controls needed.
You may use some of the equipment shown in Figure 1 and any other laboratory apparatus.
c.[3]
Explain how gravitropism in a plant root helps the plant to survive.