Weight of air
Depending on elevation, the air pressure
varies. This is because of the weight of the air that is exerting pressure on
earth. At higher elevation, there is less layer of air that is exerting pressure
so the atmospheric pressure is also less. At lower altitudes or at sea level,
more layer of air is exerting pressure so the atmospheric pressure is also
more. The sun’s energy has nothing to do with air pressure. The energy that the
Earth gets from the sun is more or less constant. The same with density of
nitrogen, and the earth’s magnetic field, they have nothing to do with air
pressure.
It's C , i'm 100% positive
It means an organism respire without it
so that organism know as anaerobic
for example : bacteria eats human and animal dead bodies under the earth there O² is deficient so bacteria respire with oxygen O²
