5 - Energy
The air that surrounds Earth is called the atmosphere. Compared to the size of the Earth, the atmosphere is very, very thin. It’s made from gases – mainly nitrogen, oxygen, and water vapor, with a little argon, carbon dioxide, xenon, neon, helium, and sulfur. The atmosphere does a lot for Earth. It blocks ultraviolet light and burns up a lot of meteors. It traps in heat, keeping Earth cozy. Even clouds are formed in the atmosphere – keeping the Earth wet with rain.