Microalgae are grown in a closed cultivation tank under bright light at a suitable constant temperature. At first, the water contains very little dissolved carbon dioxide. A solution that releases carbon dioxide is added. Which statement correctly predicts the effect on photosynthesis?
The rate decreases because carbon dioxide is a product of photosynthesis that builds up in the water.
The rate stays the same because light intensity is the factor limiting the rate.
The rate increases because carbon dioxide is a raw material that was limiting the rate.
The rate increases because carbon dioxide supplies the energy that the algae need for photosynthesis.
68 exam-style questions on AQA GCSE Biology 4.1 Photosynthesis, covering 4.1.1 Photosynthetic reaction, 4.1.2 Rate of photosynthesis, and 4.1.3 Uses of glucose from photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.