Two similar spinach plants with the same total leaf area are placed in separate transparent gas-exchange chambers. Chamber A is supplied with air containing 0.04% carbon dioxide. Both chambers are kept at 25 ∘C25\,^\circ\text{C}25∘C and receive the same light intensity. The carbon dioxide uptake per minute is measured in each chamber.
Describe what condition should be used in chamber B and how the measurements would show whether carbon dioxide concentration is limiting the rate of photosynthesis in chamber A.
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.