Ecologists are assessing four sites in a restored river for freshwater snails and juvenile freshwater mussels. Freshwater snails need a dissolved oxygen concentration of at least 4.0 mg/dm3. Juvenile freshwater mussels need a dissolved oxygen concentration of at least 7.0 mg/dm3.
Sensors monitored the water continuously for one month. The table gives the lowest dissolved oxygen concentration recorded at each site.
| Site | Lowest dissolved oxygen concentration / mg/dm3\text{mg/dm}^3mg/dm3 |
|---|---|
| J | 3.8 |
| K | 5.6 |
| L | 7.0 |
| M | 8.4 |
Which conclusion follows from the data?
The oxygen requirements of both species were met throughout the month at three sites.
The oxygen requirements of both species were met throughout the month at four sites.
The oxygen requirements of both species were met throughout the month at one site.
The oxygen requirements of both species were met throughout the month at two sites.
82 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.