The answer is true idk how to explain its just true sometimes but its super rare
<span>B) He noticed four-fifths of the air had been used up. If by air this question is referring to oxygen, the fact that it has been used up means it has reacted, mean a substance has combusted.</span>
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I think it just all exists at once, if it never is created or destroyed. It must have just appeared at the same time at some point. It doesn't exactly come from anywhere, but that's my opinion. There might be another scientific answer out there, but that's what i think. I hope this helps.
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