Teens who bum cigarettes every now and then find that addiction can happen before they know it. iStockphoto.com hide caption

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This colorized image shows part of the Ebola virus. The often-fatal Ebola hemorrhagic fever has appeared sporadically since its initial recognition in 1976. Frederick Murphy/CDC hide caption

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Called red currant tomatoes, these Solanum pimpinellifolium are actually a tomato cousin, in the nightshade family. The fruits are intensely tomato-flavored and very sweet. Harry Klee hide caption

itoggle caption Harry Klee

Scientists report they have made a living cell from DNA that was originally synthesized in a lab. iStockphoto.com hide caption

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