The answer is Index fossils its the only answer it could be
One mole of oxygen gas, which has the formula O2, has a mass of 32 g and contains 6.02 X 1023 molecules of oxygen but 12.04 X 1023 (2 X 6.02 X 1023) atoms, because each molecule of oxygen contains two oxygen atoms.
<span>Which is an IUPAC name for a covalent compound?. . A. carbon dioxide</span>
I think is cells is the function