A grower notices that the leaves of some tomato plants have changed in appearance. Which change suggests that the plants are infected with tobacco mosaic virus?
A mosaic pattern of discoloured areas spread across the leaves
A set of black spots surrounded by yellow areas on the leaves
A layer of white powder spreading across the upper leaf surface
A group of holes with brown edges near the middle of the leaves
176 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.