Answer:
So there's a simple explanation for the Great Oxidation Event. It was the cyanobacteria, pumping out unwanted oxygen, that transformed Earth's atmosphere. ... That means the cyanobacteria were busy pumping out oxygen for at least half a billion years before oxygen started appearing in the air.
Explanation:
The answer is
<span>D) hepatopancreatic ampulla
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Answer:
A frogs heart has 3 chambers. Two atria and a single ventricle.