A student measures the rate of photosynthesis by counting the bubbles of gas given off by pondweed. Which change to the method would give a more accurate measure of the volume of gas produced?
Collect the gas in a gas syringe and read the volume.
Use a brighter lamp so that more bubbles are made.
Count the bubbles for 30 seconds instead of 1 minute.
Use a larger piece of pondweed in the test tube.
117 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.