A researcher investigates photosynthesis in equal masses of cress seedlings. The light intensity, temperature and starting carbon dioxide concentration are the same for each measurement.
| Measurement | Carbon dioxide taken up in cm³ | Recording time in seconds |
|---|---|---|
| 1 | 2.8 | 60 |
| 2 | 3.0 | 60 |
| 3 | 1.5 | 30 |
| 4 | 3.2 | 60 |
Calculate the mean rate of carbon dioxide uptake in cm³ min⁻¹. Explain whether measurement 3 should be included in this calculation.
87 exam-style questions on Edexcel GCSE Biology 6.1 Photosynthesis, covering 6.1.1 Photosynthetic organisms as producers, 6.1.2a Limiting factors on the rate of photosynthesis, 6.1.2b Interactions of limiting factors on photosynthesis, and 6.1.3 Inverse square law and light intensity. Each one has a worked solution and a mark scheme showing where the marks go.