Intro

==== The earth is a very hospitable planet. Earth can support life and has a very comfortable average temperature of about 60 degrees F degrees. It also has a thin atmosphere that protects us from deadly UV rays. That atmosphere is made up of 78% nitrogen, 21% oxygen, and 1% other gases, making it perfect for different species of life to breath. The Earth's surface is about 71% water and 29% land that contains rock, assorted minerals, vegetation, and dirt. ====

What we know