Four young and healthy sea lions the Pacific Marine Mammal Center cared for make a quick dash back into the ocean. Courtesy of Pacific Marine Mammal Center hide caption

itoggle caption Courtesy of Pacific Marine Mammal Center

A worker at Ford's assembly plant in Wayne, Mich., installs back seats made from soy-based foam in a Ford C-Max. Jason Margolis/NPR hide caption

itoggle caption Jason Margolis/NPR

President Obama's environmental plan won't be so hard for states that have moved to cut emissions. But for others it will be more difficult. Scott Olson/Getty Images hide caption

itoggle caption Scott Olson/Getty Images

"Anytime you're in the wild with a beautiful animal you're going to feel good," says Susan Casey, author of Voices in the Ocean: A Journey into the Wild and Haunting World of Dolphins. Penguin Random House hide caption

itoggle caption Penguin Random House

A coal scraper machine works on a pile of coal at American Electric Power's Mountaineer coal power plant in 2009 in New Haven, W.Va. The state, in which coal mining is a major industry, is one party planning to sue the Environmental Protection Agency regarding new power plant regulations announced Monday. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

Ready, set, fly! The ball bearings glued to this bumblebee's legs simulate the weight and placement of pollen loads. The tag on the insect's back is a lightweight sensor, designed to track its movements in flight. Courtesy of Andrew Mountcastle hide caption

itoggle caption Courtesy of Andrew Mountcastle