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REMNANTS OF THE PAST |
Geologists have long wondered when oxygen made its debut as a leading gas in Earth's life support system. They knew there were significant amounts present at least 1.2 billion years ago, because evidence suggested that the earliest land-based life--microbial mats and the like--appeared at that time. But two recent studies push the date back nearly twice as far.
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Add Commentdesckib every single thing about the 1# FIRST ICE AGE EVERY IN HISTORYS HISTORY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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