A school plant nursery compares three tests using plants from the same batch. In each test, only the named condition is changed; the other conditions are kept the same. The rate of photosynthesis is measured before and after the change.
| Test | Condition changed | Before | After | Rate before (arbitrary units) | Rate after (arbitrary units) |
|---|---|---|---|---|---|
| 1 | Light intensity (arbitrary units) | 20 | 60 | 10 | 24 |
| 2 | Carbon dioxide concentration (%) | 0.04 | 0.10 | 12 | 22 |
| 3 | Temperature (∘C^{\circ}\text{C}∘C) | 15 | 25 | 8 | 20 |
Use the data to explain which condition was limiting the rate of photosynthesis before the change in each test.
117 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.