A grower finds 5 infected plants in a greenhouse. The number of infected plants doubles every 3 days. How many plants will be infected if the grower waits 9 days before removing them?
15 plants
20 plants
40 plants
80 plants
58 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.