A patch of moss is enclosed beneath a transparent hood in dim light. The carbon dioxide concentration beneath the hood falls slowly.
The air beneath the hood is then warmed by 5 °C. Light is still the limiting factor, so the rate of photosynthesis does not change. The moss respires faster, but its rate of respiration stays lower than its rate of photosynthesis.
Which statement describes and explains the change in the carbon dioxide concentration beneath the hood after the air is warmed?
The concentration falls more slowly because respiration releases carbon dioxide.
The concentration falls at the same rate because photosynthesis has not changed.
The concentration falls more quickly because respiration takes in carbon dioxide.
The concentration starts to rise because the moss is now respiring faster.
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.