Question

what happens as the air reaches the nasal cavity ?? why is it not advisable to breathe through the mouth ???​

Answer 1

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A mucous membrane lines your nasal cavity and it helps keep your nose moist. Little hairs inside your nasal cavity help filter the air you breathe in, and block dirt and dust from getting into your lungs. When you breathe in through your mouth, or oral cavity, the air is moistened, but not filtered.

Answer 2

Answer:

The air enters through the nostrils are moistened by the mucous membrane lines in the nostrils.

It is not advisabld to breathe through the mouth because in the nose there are nostrils hairs which prevents the entering of dust particles and purifies it and in the case of mouth the air is not purified and the main reason is moistened air in the nostrils.