A barley crop has powdery mildew. The wind blew from west to east during the week when the grower recorded newly diseased plants at different distances from the infected plants.
| Direction from infected plants | Distance | Newly diseased plants |
|---|---|---|
| East | 0–10 m | 31 |
| East | 10–20 m | 18 |
| East | 20–30 m | 7 |
| West | 0–10 m | 2 |
Use the results to explain the likely route by which the disease spread. Suggest how the distribution of newly diseased plants might change if the wind direction reversed.
181 exam-style questions on OCR GCSE Biology 6.3 Monitoring and maintaining health, covering 6.3.1 Health and disease, 6.3.2 Interactions between diseases, 6.3.3 Spread of communicable diseases, 6.3.4 Common infections and diseases, 6.3.5 Physical plant defence responses, 6.3.6 Chemical plant defence responses, 6.3.7 Detecting and identifying plant diseases, 6.3.8 White blood cells and platelets, 6.3.9 Non-specific defence systems, 6.3.10 The immune system, 6.3.11 Monoclonal antibodies, 6.3.12 Vaccines and medicines, 6.3.13 Aseptic techniques, 6.3.14 Discovery and development of new medicines, 6.3.15 Causes of non-communicable diseases, 6.3.16 Treatments for cardiovascular disease, 6.3.17 Lifestyle factors and non-communicable diseases, 6.3.18 Cancer, 6.3.19 Stem cells in medicine, 6.3.20 Gene technology in medicine, and 6.3.21 The human genome and medicine. Each one has a worked solution and a mark scheme showing where the marks go.