A researcher measures the oxygen released by an aquatic moss over two minutes, using two methods.
Method P: count the bubbles of gas released.
Method Q: measure the total volume of gas that collects in a gas syringe.
Which statement correctly compares the precision of the two methods?
Method Q is more precise, because bubbles vary in size but the syringe measures the total volume of gas.
The methods are equally precise, because both record the gas released in two minutes.
Method P is more precise, because each bubble released holds the same volume of gas.
Method Q is more precise, because the syringe collects only oxygen and none of the other gases.
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.