The diagram shows apparatus that can be used to measure the rate of anaerobic respiration of yeast. [Figure 17 - Diagram of apparatus with scale, clip, rubber tubing, glass tube, capillary tube, coloured liquid, yeast suspension in sugar solution] Which precautions must be taken during the setting up of this apparatus? P A layer of oil must be poured over the surface of the yeast suspension. Q The clip must not be closed until the yeast suspension has had time to reach room temperature. R The coloured liquid must be near the right hand end of the capillary tube. S The yeast suspension must be made with boiled and cooled water.

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