Moles, mass, Avogadro? How do these terms fit together?

We know the mass of a mole of any element is equal to its atomic mass in grams and that mass contains the Avogadro number of atoms.

But what about oxygen, which exists as an atom and a molecule.

Order the items below from largest to smallest size.

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1 mole of oxygen
1 molecule of oxygen
1 atom of oxygen
3.01 X 1023 atoms of oxygen
4 grams of oxygen