Earth's Atmosphere: A jacket for the planet

Read the sentence from the section "The Active, Changing Layer." (See Image)
What does the word "excited" convey in the sentence?

• It conveys a sense of being agitated.
• It conveys a sense of being energized.
• It conveys a sense of being awakened.
• It conveys a sense of being enticed.

The author uses a playful tone in much of the article.
Which selection from the article BEST reflects that tone?

• Earth's atmosphere has six different layers -- the troposphere, stratosphere, mesosphere, thermosphere, ionosphere, and exosphere. They go from the ground all the way to outer space.
• The mesosphere is 22 miles (35 kilometers) thick. The mesosphere starts just above the stratosphere and extends to 53 miles 85 kilometers) from the Earth's surface. The air is still thin, so you wouldn't be able to breathe up in the mesosphere.
• When you feel the wind on your face, see clouds in the sky, and watch a bird flap its wings in flight, you're experiencing the troposphere. It's a pretty nice layer to call home.
• Its a very active part of the atmosphere, and it grows and shrinks depending on the energy (radiation) it absorbs from the sun. Its name comes from the fact that gases in these layers are excited by solar radiation to form "ions," which have an electrical charge.

What limitation does the diagram in the section "One Atmosphere, Many Layers" have that the rest of the article does not have?

• It does not show where the troposphere is in relation to other layers.
• It does not provide visual evidence of different layers.
• It does not help the reader to understand how far the mesosphere extends.
• It does not identify the relative location of the ionosphere.

Examine the image included with the section "The Active, Changing Layer." 
How does the image enhance the reader's understanding of the ionosphere beyond what the section offers?

• The image helps to depict the distance between the ionosphere and the troposphere.
• The image helps the reader to understand what happens when particles from the sun interact with particles in the ionosphere.
• The image helps to explain why auroras typically happen in the ionosphere near Earth's poles.
• The image helps the reader to visualize the color and brightness of the magnetic field found within the ionosphere.

The aurora borealis is also called the ____________________.

• Stop Lights
• Southern Lights
• Northern Lights
• Colorful Lights

Our atmosphere does many things such as _____________.

• keeping us warm
• providing organisms oxygen
• protecting living things from uv radiation
• All of the above

Earth's atmosphere is __________.

• thick
• thin

"Tropos" means _________.

• middle
• change
• heat
• layers

"Meso" means _________.

• middle
• change
• heat 
• layer

"Strat" means _________.

• middle
• change
• heat 
• layer