The outer planets — Jupiter, Saturn, Uranus, and Neptune are made up of: <em><u> </u></em><em><u>h</u></em><em><u>ydrogen</u></em><em><u> </u></em><em><u>and</u></em><em><u> </u></em><em><u>helium</u></em><em><u> </u></em>
I would have to go with Sewage mostly because it smells and because it can really hurt the environment. Plants can die and it just is gross to smell. So this would definitely pollute the earth. I hope this helped! :D
