In an experiment a student extracted some saliva into a test tube then mixed it with some starch to form a solution. He prepared another test tube containing starch solution only. He incubated both test tubes in a water bath at 37°C for two hours then tested for starch with iodine solution in each test-tube. a) Give the observations that were made in the following test tubes and give reasons for your answer. (i) (ii) Starch+saliva Starch only (iii) Name the active compound in the saliva that was being investigated. (iv) Explain the results obtained in a(i) above. b) Why were both test tubes incubated at 37°C.​