1. Evolution
Eventually their food source of organic compounds ran low so they had to come up with another source of energy thus the autotroph emerged. ... Then the heterotrophs took in the autotrophs as an energy source. This made a never-ending cycle of energy. The heterotrophs had been using oxygen for their respiration, the oxygen, like the organic compounds started to run low so there need to be another source for respiration. ... They started creating together, destroying each other which made energy. ...
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- Approx Pages: 3
- Grade Level: High School