A council worker surveys newly planted street trees. Some of the trees have areas of decay and malformed leaves.
An identification website gives pathogen P and pathogen Q as possible causes of these signs. The worker uses a monoclonal antibody testing kit that detects pathogen P only. Samples from every tree showing signs give a negative result.
The table shows the survey results.
| Day | Number of trees showing signs |
|---|---|
| 0 | 8 |
| 6 | 20 |
Calculate the percentage increase in the number of trees showing signs from day 0 to day 6.
Explain why the information from the website and the testing kit is not enough to identify pathogen Q as the cause.
The worker removes the trees showing signs immediately and sends samples to a laboratory.
Explain both decisions.
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.