Activity 6.3 NCERT class 10 science chapter 6 Life processes
Brief procedure: Activity asks us to take a starch solution in the test tube, treat it with saliva and then check for the presence of starch through iodine.
Observation: Iodine does not turn starch treated with saliva into blue colour.
Explanation: Saliva contains salivary amylase enzyme. It degrades starch into simple sugar. Iodine does not act on the simple sugar. Hence solution treated with saliva is not turned blue.
Inference: Saliva degrades the starch.