The Precambrian started at 4.6 billion years ago and ended at 544 million years old. Precambrian time took up a huge chunk of history. It was longer than any other era. The climate at the start was hot and the earth had molten lava. The earth cooled. The water vapor that was in the air made it rain and it made oceans. The carbon dioxide levels started to rise forming and ozone layer that blocked out harsh rays of sun. The oceans nearly covered the earth except for a small ancient continent. This continent ran through the middle of the earth on both sides of the equator. A plant was a Sea anemones. Two animals were Jellyfish and multicellular organisms. At the end of the Precambrian time scientist believe that the first mass extinction happened. And a ice age might have caused the first mass extinction.
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