Two ponds have the same temperature, light intensity and number of fish. Each fish requires a dissolved oxygen concentration of at least 5 mg/dm3 to remain active.
The table shows measurements made on one day.
| Time | Oxygen in pond P / mg/dm3\text{mg/dm}^3mg/dm3 | Oxygen in pond Q / mg/dm3\text{mg/dm}^3mg/dm3 |
|---|---|---|
| Before sunrise | 3 | 6 |
| Midday | 7 | 8 |
| Sunset | 9 | 7 |
Which conclusion follows from these measurements?
Fish in P can remain active throughout the day because its mean exceeds 5.
Fish in Q become inactive at sunset because its oxygen concentration is falling.
Fish in P may become inactive before sunrise despite its higher sunset reading.
Fish in Q face greater oxygen shortage because its maximum reading is lower.
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.