The Atmosphere is...

• A. A thin layer of gases surrounding Earth
• B. The rigid outer part of the Earth
• C. All the water at and near the surface of the earth
• D. The energy of the sun

Answer: (A)

The atmosphere is a thin layer of gases surrounding Earth, held by gravity. It forms a gaseous envelope that extends from the surface up into space and is the air we breathe. This layer supports life, drives weather and climate, and shields us in part from harmful solar radiation (thanks to features like the ozone layer). It’s not the rigid outer part of the Earth—that would be the crust and lithosphere—nor all the water at and near the surface—that’s the hydrosphere—nor the energy of the sun, which is solar radiation.