These mitochondria, in red, are from the heart muscle cell of a rat. Mitochondria have been described as "the powerhouses of the cell" because they generate most of a cell's supply of chemical energy. But at least one type of complex cell doesn't need 'em, it turns out. Science Source hide caption

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Humpback whale and calf, off the Revillagigedo Islands, Mexico. Reinhard Dirscherl/Look-foto/Corbis hide caption

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It Took A Musician's Ear To Decode The Complex Song In Whale Calls

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By the 1960s, humpback whales and other whale species had been hunted extensively, sometimes to the point of near extinction. Then a recording of humpback whale songs helped shift public opinion on the hunting of all whale species. Luis Robayo/AFP/Getty Images hide caption

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Recordings That Made Waves: The Songs That Saved The Whales

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Gold exists, just as it really is, just as the physicist knows it to be, and that has nothing to do with us. Michal Cizek/AFP/Getty Images hide caption

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Kind of cute. But pretty stupid. A scale model of a baby sauropod in its egg. Tim Boyle/Getty Images hide caption

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Many of life's building blocks can be found in the objects bombarding Earth from outer space. Does that mean that life, too, developed elsewhere before arriving here? Mary P. Hrybyk-Keith/NASA hide caption

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For centuries, Russians believed putting a brown frog in their milk would keep it fresh. Now scientists are finding chemicals in the frog's slimy goo that inhibit the growth of bacteria and fungi. Stefan Arendt/Corbis hide caption

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Moss and a cup fungus growing amid the decomposing leaves of Shakerag Hollow in Sewanee, Tennessee. Courtesy of David Haskell hide caption

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