Great for elementary and middle school as an intro to new material. This article focuses on the different types of organisms on our planet: ones that need oxygen and ones that don't. Scientists believe the first life on the planet were anaerobic and that over time gained the ability to use photosynthesis to create usable energy. The atmosphere may have been inhabitable for people at the beginning of our planet and these organisms slowly changed it over time to enable aerobic organisms to flourish.
Vocab words: anaerobic, aerobic, photosynthesis, oxygen
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