2 Answer ALL questions. Write your answers in the spaces provided. 1 (a) Describe how oxygen from the air is able to reach insect muscle cells. 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(b) A respirometer was used to compare the rate of aerobic respiration of two species of insect. The diagram shows the respirometer. syringe three-way tap glass tubing small insects gauze glass tube scale coloured liquid soda lime (i) Give the units for a valid comparison of the rate of respiration of these two species of insect. (1) .................................................................................................................................................................................................................................................................................... 3 Turn over (ii) Other factors may affect the results from this respirometer. Describe how one named factor could be controlled when using this respirometer. 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(iii) Explain why the soda lime in the tube must be replaced when the other species of insect is placed in the respirometer. 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(Total for Question 1 = 8 marks)