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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A health official takes a blood sample from a child's finger for a malaria test at a clinic in Bong Ti Lang village on the Thai-Myanmar border. Narong Sangnak/EPA /LANDOV hide caption

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