Scientists surveyed five similar ponds beside farmland. For each pond, they recorded the concentration of fertiliser in the water and the number of aquatic animal species present.
| Concentration of fertiliser / mg per dm³ | 1 | 2 | 4 | 8 | 16 |
|---|---|---|---|---|---|
| Number of aquatic animal species | 15 | 15 | 13 | 9 | 4 |
Which conclusion is supported by these results?
The number of aquatic animal species is unchanged between 1 and 2 mg per dm³, then is lower at each higher concentration
The pond at 16 mg per dm³ contains fewer individual aquatic animals than every pond at a lower concentration
The ponds at 1 and 2 mg per dm³ contain exactly the same aquatic animal species as each other
The fertiliser concentration alone caused the differences in the number of aquatic animal species among the five ponds
84 exam-style questions on AQA GCSE Biology 7.3 Biodiversity and the effect of human interaction on ecosystems, covering 7.3.1 Biodiversity, 7.3.2 Waste management, 7.3.3 Land use, 7.3.4 Deforestation, 7.3.5 Global warming, and 7.3.6 Maintaining biodiversity. Each one has a worked solution and a mark scheme showing where the marks go.