What belong in the respiratory system?

Answer 1

The human respiratory system is adapted to breath the air on Earth, which is:

Nitrogen (N2): 78.084%

Oxygen (O2): 20.946%

Argon (Ar): .9340%

Water vapor (H2O): .4%

Carbon Dioxide (CO2): .039445%

Neon (Ne): .001818%

Helium (He): .000524%

Methane (CH4): .000179%

Krypton (Kr): .000114%

Hydrogen (H2): .000055%

Nitrous oxide (N2O): .00003%

Carbon monoxide (CO): .00001%

Xenon (Xe): .000009%

Ozone (O3): .000007%

Nitrogen dioxide (NO2): .000002%

Iodine (I2): .000001%

Ammonia (NH3): minimal traces

Humans are not known to be able to breathe any drastically different type of air.