With the question “What is life?” addressed at the molecular level, humanity could finally cure all disease and live forever… Except, not really. It turns out we're complicated. *** Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse Thanks to the following patrons for their generous monthly contributions that help keep Crash Course free for everyone forever: Eric Prestemon, Sam Buck, Mark Brouwer, Laura Busby, Zach Van Stanley, Bob Doye, Jennifer Killen, Naman Goel, Nathan Catchings, Brandon Westmoreland, dorsey, Indika Siriwardena, Kenneth F Penttinen, Trevin Beattie, Erika & Alexa Saur, Glenn Elliott, Justin Zingsheim, Jessica Wode, Tom Trval, Jason Saslow, Nathan Taylor, Brian Thomas Gossett, Khaled El Shalakany, SR Foxley, Yasenia Cruz, Eric Koslow, Caleb Weeks, Tim Curwick, D.A. Noe, Shawn Arnold, Malcolm Callis, William McGraw, Andrei Krishkevich, Rachel Bright, Jirat, Ian Dundore -- Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Tumblr - http://thecrashcourse.tumblr.com/ Support Crash Course on Patreon: http://patreon.com/crashcourse CC Kids: null