Life-Supporting Atmospheric Functions

      1.  O₂ is used by animals for respiration.

        2.  Provides pressurization necessary for the existence of liquid water.  (Without it, oceans, rivers, lakes,
             cloud droplets and body fluids would convert to water vapor by boiling.)

        3.  Insulation keeps the nighttime and winter temperatures of the earth's surface much warmer than they
             would otherwise be and keeps daytime and summer temperatures (surface) lower than they would
             otherwise be.

        4.  Heat distribution cools the tropics, warms high-latitude areas and moderates seasonal temperature
             fluctuations.

        5.  H₂O distribution brings water to inland areas.

        6.  Shielding from destructive ultraviolet rays, x-rays and gamma-rays (all forms of electromagnetic
             radiation) and from the impacts of cosmic rays (subatomic and atomic material particles) and
             meteoroids.