An instrument above an area of open grassland measures the net transfer of carbon dioxide between the grassland and the atmosphere. Photosynthesis and respiration are the only processes affecting this transfer.
The table shows measurements made on one day.
| Measurement | Result |
|---|---|
| Net carbon dioxide transferred from the atmosphere into each square metre of grassland during 10 hours of daylight | 30.0 g m⁻² |
| Carbon dioxide released by respiration from each square metre of grassland during 4 hours of darkness | 6.0 g m⁻² |
The rate of respiration is the same in daylight and in darkness.
Calculate the mean rate at which carbon dioxide is used in photosynthesis during daylight.
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.