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Earth's breathable atmosphere tied to plate tectonics?
2014-06-20 07:20:00| Climate Ark Climate Change & Global Warming Newsfeed
PhysOrg: The rise of oxygen is one of the biggest puzzle in Earth's history. Our planet's atmosphere started out oxygen-free. Then, around 3.5 billion years ago, tiny microbes called cyanobacteria (or blue-green algae) learned out to carry out photosynthesis. They began using energy from sunlight to make their food from carbon dioxide and water, giving off oxygen as waste. But it took another 3 billion years for oxygen levels to climb from trace amounts to at least 20 percent of the atmosphere, or high...
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Category:Electronics and Electrical