Paheli kept some water in a beaker for heating. She observed that tiny bubbles appeared before the water started to boil. She boiled the water for about 5 minutes and filled it in a bottle up to the brim and kept the bottle air-tight till it cooled down to room temperature.

(a) Why did the tiny bubbles appear?

(b) Do you think tiny bubbles will appear on heating the water taken out from the bottle? Justify your answer.