a.[2]
Gardeners can use plant hormones to control plant growth. What are two commercial uses of synthetic auxins? Tick (✓\checkmark✓) two boxes.
- To start seed germination
- To promote flower production
- As weed killers
- To ripen harvested fruit
- As rooting powders for cuttings
b.[3]
Students investigated the effect of gravity on the direction of root growth in bean seedlings. Figure 1 shows the experimental setup.
Describe two improvements the students should make to their investigation.
c.[1]
Figure 2 shows a horizontal seedling root bending downwards in response to gravity.
Suggest how the students could accurately measure the length of the curved root in Figure 2.
d.[3]
Explain how the unequal distribution of auxin causes the root in Figure 2 to bend downwards. Refer to Side A (upper side) and Side B (lower side) in your answer.