A farmer grows tomato plants in a greenhouse during winter.
The farmer burns paraffin in a heater inside the greenhouse. Burning paraffin releases heat and carbon dioxide.
Explain how burning paraffin in the greenhouse increases the rate of photosynthesis of the tomato plants.
The farmer also switches on lamps in the greenhouse on winter evenings.
Explain how this increases the yield of tomatoes.
The farmer increased the carbon dioxide concentration in the greenhouse even further. The rate of photosynthesis did not increase.
Suggest why.
44 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.