To find out how water temperature affects photosynthesis, a class placed Elodea in sodium hydrogencarbonate solution in a water bath. They recorded the oxygen collected over five minutes at each temperature and calculated a rate. Which variable must be kept the same in this investigation?
The concentration of the sodium hydrogencarbonate solution
The rate calculated from the oxygen collected
The temperature at which the rate is highest
The temperature of the water bath
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.