A gardener is growing tomato plants in a greenhouse. One of the plants, Plant A, becomes infected with a wind-dispersed fungal disease.
Figure 1 shows a plan of the greenhouse layout.
a.[2]
Which plant in Figure 1 is the fungus likely to spread to first from Plant A? Give a reason for your answer.
b.[1]
Suggest one physical action the gardener could take to reduce the spread of this fungal disease to the other tomato plants, without using chemical fungicides.