Gravitropism (also known as geotropism) is a growth response of a plant to gravity.
a.[2]
Name one other plant tropism besides phototropism and gravitropism. 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 direction of growth of germinating plant roots.
Include details of any controls needed.
You may suggest using standard laboratory equipment, such as Petri dishes, bean seedlings, damp cotton wool, adhesive tape, and a dark cupboard.
c.[3]
Explain how positive gravitropism in a plant root helps the plant to survive.