They started playing and at the end of the game, all three of them were panting and breathing heavily. Sam noticed that John was breathing through his mouth so he advised him to breath through nose and not through mouth.
To this Kenneth said ' how does it matter? we will be inhaling the same air whether we breathe through nose or through mouth'.
Sam gave a reasonable explanation to make Kenneth and John understand that they should breathe through our nose and not through our mouth.
What was explanation given by Sam?
Sam advised Kenneth and John to breathe through nose and not through mouth because he knew that air around us has dust particles in it. Breathing through mouth may allow dust particles to enter our respiratory system which may cause serious health issues and breathing problems. Fine hair and mucus present inside the nose prevent dust particles from getting into the respiratory system and hence we should always breathe through our nose and not through mouth.