Two groups of heather plants are identical except that group P makes chemical X and group Q does not. The same number of bacteria is introduced into the leaves of each plant.
Which observation would support the conclusion that chemical X is an antibacterial defence?
More living bacteria are found inside the leaves of group P than group Q.
Similar numbers of living bacteria are found inside the leaves of groups P and Q.
Fewer living bacteria are found inside the leaves of group P than group Q.
Fewer insects feed on the leaves of group P than on the leaves of group Q.
133 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.