What percent of Earth's atmosphere is composed of Nitrogen?

• 1%
• 21%
• 78%
• 100%

A device that is uses a wet and dry bulb to measure _____________ is the sling psychrometer. 

• air currents
• air temperature 
• light intensity 
• relative humidity 

Which of the following gases is found in the stratosphere but NOT the tropsphere?

• ozone
• oxygen
• nitrogen
• carbon dioxide

Groundwater moves from the ground through plants and then back into the atmosphere through the process of

• condensation
• precipitation
• run-off
• transpiration

An anemometer is used to track  ______________. 

• temperature 
• precipitation
• humidity
• wind speed

Why is rain likely when warm, moisture-laden air meets cold air?

• The cold air moves faster and pushes the warm air away, causing condensation and rain.
• The lighter warm air will rise and cool down, causing transpiration and rain.
• The moisture in the warm air condenses on contact with the cold air, causing rain to fall.
• The cold air mixes with the warm air, reducing its temperature causing moisture to condense.

A special cloud called ______ is formed close to the ground when moisture condenses as air is cooled from below.

• dew
• nimbus
• fog
• stratus

What forms when air masses with different temperatures meet?

• storms
• thunder
• fronts
• currents

How is the sun the major source of energy in the water cycle?

• It provides the energy to condense atmospheric water vapor into rain.
• It provides the energy to evaporate water on Earth into the atmosphere.
• It provides the energy needed for water to be transported downhill from mountains to rivers and oceans.

What front does this symbol represent?

• cold
• warm
• stationary
• occluded