Environmental Science
In a volume of air near the earth's surface, ____ occupies 78 percent and ____ nearly 21 percent.

Nitrogen, water vapor
Oxygen, hydrogen
Hydrogen, helium
Nitrogen, oxygen
Hydrogen, oxygen

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Environmental Science
The atmospheric greenhouse effect is produced mainly by the:

Absorption and re-emission of visible light by the ground
Absorption and re-emission of ultraviolet radiation by the atmosphere
Absorption and re-emission of visible light by clouds
Absorption and re-emission of visible light by the atmosphere
Absorption and re-emission of infrared radiation by the atmosphere

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