Geological Time

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During the early Paleozoic era, South America, Africa, Australia, Antartica, India and perhaps China comprised the vast southern continent of

What is the major source of free oxygen in the atmosphere?

The most common Precambrian fossils are layered mounds of calcium carbonate called

The era of ancient life iis know as the

Laurasia was made up of which modern continents

Some continents contain large core area of Precambrian rocks called

The largest expanse of time on the geological time scale is the

Which of the followig gases was NOT part of Earth's original atmosphere?