About 2.7 billion years ago, the primordial seas already hosted the first photosynthetic microbes, the blue-green algae that took in carbon dioxide and released oxygen into the air. But they were outnumbered by
About 2.7 billion years ago, the primordial seas already hosted the first photosynthetic microbes, the blue-green algae that took in carbon dioxide and released oxygen into the air. But they were outnumbered by
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