Three groups of identical young plants were grown under different light intensities. Water and mineral ions were supplied in amounts that did not limit growth. The temperature and the number of plants in each group were the same.
| Group | Light intensity / lux | Mean increase in height in 7 days / cm |
|---|---|---|
| P | 25 000 | 12.3 |
| Q | 5 000 | 4.8 |
| R | 15 000 | 9.1 |
Use the data to explain why group Q had a smaller mean increase in height than group P.
Predict the mean increase in height in 7 days for a group grown at 10 000 lux. Justify your prediction using the data.
82 exam-style questions on Edexcel GCSE Biology 9.1 Ecosystems and interdependence, covering 9.1.1 Levels of organisation in ecosystems, 9.1.2 Abiotic and biotic factors, 9.1.3 Importance of interdependence, 9.1.4 Parasitism and mutualism, and 9.1.5 Determining number of organisms in an area. Each one has a worked solution and a mark scheme showing where the marks go.