A researcher compares the rate of photosynthesis of a bean plant at four carbon dioxide concentrations. The concentrations are tested from lowest to highest during one afternoon. Although the lamp stays at the same distance, the temperature inside the chamber rises throughout the investigation.
Which change would best reduce the effect of this unwanted temperature change?
Return the chamber to the same starting temperature before each test.
Test the concentrations in order from highest to lowest instead.
Move the lamp further away each time the chamber warms up.
Record the chamber temperature at the end of each test.
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.