March 31, 2010 (21 images)

Updated: March 31, 2010 at 6:12 PM
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U.S. President Barack Obama looks at an F-18 "Green" Hornet, which is being tested to run off biodiesel, after delivering remarks on energy security at Joint Base Andrews Naval Air Facility in Maryland on March 31, 2010. UPI/Kevin Dietsch
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