b) temp effects rate of amylase action. Higher temp = Higher rate so expect all done for 60 and potential one cross at 120s for 40.
(0.15/1.35) × 100
B) To allow the sudents to compare results for example
C) You'll need to draw a graph with a labelled axis and equal values and a line of best fit
Hope this helps, good luck with the rest of your questions!