Swimming in the sweet spot: How marine animals save energy on long journeys
Competitive swimmers know that swimming underwater causes less drag resistance than swimming at the surface. Splashing around ...
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The Permian extinction—when life nearly came to an end
About 250 million years ago, at the end of the Permian period, something killed some 90 percent of the planet's species. Less than 5 percent of the animal species in the seas survived. On land ...