A public health team investigated whether fitting tight covers to household rainwater tanks could reduce malaria. Every rainwater tank in area P was fitted with a tight cover after the first measurements were taken. The tanks in area Q were left uncovered.
The team recorded results at the start of the investigation and six months later.
| Area | Treatment | Mean number of mosquito larvae per tank at the start | Mean number of mosquito larvae per tank after six months | Malaria cases per 1000 people at the start | Malaria cases per 1000 people after six months |
|---|---|---|---|---|---|
| P | Tight covers fitted | 18 | 3 | 42 | 16 |
| Q | Tanks left uncovered | 17 | 19 | 40 | 44 |
Explain why the results support fitting tight covers to rainwater tanks as a way of reducing the spread of malaria.
252 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.