About 500 million years ago, not a single creature had a skull. Over time, these bony plates evolved into the structural marvels that vertebrates—animals with spinal cords, aka you, me, and your pug, ...

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Add Yahoo as a preferred source to see more of our stories on Google. The skull of a child who died in the 15th or 16th century was found by workers digging a pipeline in northwest Argentina. | Credit ...