Practice mode Evolution

The first living organisms on Earth are believed to have been ____.

Correct answer C. anaerobic heterotrophic prokaryotes

Explanation

Early cells probably consumed organic molecules already present in the primitive ocean. With no free oxygen they respired anaerobically and were simple prokaryotes; photosynthesis and eukaryotes arose later.

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The first living organisms on Earth are believed to have been ____.

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The first living organisms on Earth are believed to have been ____.

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