Scientists compare plant growth under four combinations of light intensity and carbon dioxide concentration. Other conditions are controlled.
| Light intensity | Carbon dioxide concentration | Mean increase in dry mass / g |
|---|---|---|
| Low | Low | 2 |
| Low | High | 2 |
| High | Low | 5 |
| High | High | 9 |
Which conclusion is supported by the combined results?
Extra carbon dioxide increases growth at both light intensities; its effect depends on light intensity.
Extra carbon dioxide increases growth at both light intensities; its effect is independent of light intensity.
Extra carbon dioxide increases growth only at high light intensity; its effect depends on light intensity.
Extra carbon dioxide increases growth only at high light intensity; its effect is independent of light intensity.
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.