Scientists investigate whether a native beetle is affected by an introduced competitor or a new pathogen. All groups receive the same food supply and abiotic conditions.
The table shows native beetle survival as a percentage of survival when neither factor is present.
| Introduced competitor | New pathogen | Relative survival / % |
|---|---|---|
| Absent | Absent | 100 |
| Present | Absent | 80 |
| Absent | Present | 50 |
| Present | Present | 20 |
Which statement correctly compares the pathogen's effect in the two situations?
It reduces survival by 50% without the competitor and by 60% with it.
It reduces survival by 50% without the competitor and by 75% with it.
It reduces survival by 50% without the competitor and by 30% with it.
It reduces survival by 50% without the competitor and by 80% with it.
40 exam-style questions on AQA GCSE Biology 7.1 Adaptations, interdependence and competition, covering 7.1.1 Communities, 7.1.2 Abiotic factors, 7.1.3 Biotic factors, and 7.1.4 Adaptations. Each one has a worked solution and a mark scheme showing where the marks go.