Which of the following best explains why air is considered a natural resource?
AAir is expensive to produce and keep clean.
BAir is a raw material for biological processes supplied by the Earth.
CAir can be processed to generate expensive chemicals.
DNone of the above
AAir is expensive to produce and keep clean.
BAir is a raw material for biological processes supplied by the Earth.
CAir can be processed to generate expensive chemicals.
DNone of the above