After returning from school, Ram wanted to perform a small experiment in his home. He took some wheat flour and water and made a paste. He then divided the paste into two halves and put ach half separately into two test tubes A and B. He then added 10 drops of water to the paste in tube A and the same amount of saliva in tube B. After few minutes, he added a few drops of odine solution to both the test tubes and observed some colour change in tube A. Based on the bove experiment, answer the following question: a) Why was there a colour change in tube A? b) Why no colour change occurred in tube B? c) Why was saliva added in tube B?​