Question

Although nitrogen gas is more in percentage,we only inhale oxygen during respiration.why is this so?

Answer 1

no the concept is wrong, we do not only inhale oxygen but we inhale air containing all the gases in fixed percentage. but the filtration of air takes place in the alveolar sacs in lungs where oxygen is filtered out and mixed with blood.Thus the concept is we inhale air containing more of oxygen and less carbondioxide but we exhale air containing more of carbondioxide and less of oxygen.

Answer 2

we inhale many gases through our nose and dust and smoke particles but dust and smoke are filtered in nose through mucus and Celia which are small hair like projections the many gases inhaled by us are used in our body for different processes like nitrogen in protein synthesis but the use for digesting are burning the food for energy is only done by oxygen