1 .		Which one of the following is NOT included in Earth's traditional four spheres?
2 .		Which one of the following is the most abundant gas in the atmosphere?
3 .		Which one of the following is NOT included in the basic elements of weather and climate?
4 .		__________ is the variable atmospheric component that can exist in all three states (solid, liquid, and gas) at the temperatures and pressures that normally occur on Earth.
5 .		With increasing altitude, air pressure __________.
6 .		In the upper atmosphere, ozone absorbs potentially harmful __________ radiation from the Sun.
7 .		Although present in only minute amounts, along with water vapor, carbon dioxide has a significant influence on the __________ of the atmosphere.
8 .		The temperature decrease with an increase in altitude in the troposphere, called the environmental lapse rate, has an average value of __________°C per kilometer (__________°F per 1000 feet).
9 .		Water vapor represents up to about __________ percent of the volume of air near the surface.
10 .		Auroral displays, one of nature's most interesting spectacles, occur in the atmospheric layer called the __________.
11 .		Earth's four spheres and all their component parts are interrelated to produce a complex and continuously interacting whole that we call the __________.
12 .		Atmospheric pressure is caused by __________.
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