Question

it is always benefitial to inhale air through nostril , give reason .

Answer 1

Hi,
Here's your answer:

Nostrils contains hairs as well as the muscus membrane which traps the dust particles and the germs along with the air we breath in and prevents it from entering in the respiratory system ,thereby preventing any hazardous diseases. Whereas, when we breath in through mouth,the dust particles and germs directly enter our respiratory system, causing harmful diseases.Therfore, It is always benefitial to inhale air through nostrils.
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Hope it helps!

Answer 2

Nostrils are built for two fumctions: one for olfactory sense and other for inhalation. Though we can inhale through mouth also, but it is not specially bulit for it and if we breath from mouth, there are many adverse consequences such as drying of mouth, microbes may enter. But through nostrils microbes and tiny particles can rarely enter as they have mucous which obstruct them to enter our body i.e. lungs.