This is an audio version of the Chapter 20 titled "Human Actions and Earth's Resources", Section 2 "Use and Conservation of Energy" in the CK12 Earth Science for Middle School by Authors Jean Brainard and Julie Sandeen created and used under the Creative Common Attribution/Non-Commercial/Share Alike 3.0 Unported (CC-by_NC-SA) License (http://creativecommons.org/licenses/by-nc-sa/3.0/). Don't forget to say thanks at http://www.ck-12.org/saythanks
