Question

there are so many kinds of air around us but how we are able to inhale oxygen only?

Answer 1

When you inhale, you inhale the entire mix of gases in the atmosphere. Most of this gas is Nitrogen (N2) at around 80%, which is essentially inert as a gas in your body. Oxygen makes up around 20% of the atmospheric gases. With the approximate 20% of oxygen gas (O2) inhaled, you extract a small percentage and breathe back out a mix of gases (again, mostly N2) of which O2 still makes up over 10% of the gas present.

Answer 2

there r some kinds of organs which allow only o2