Answer:
whether the molecule is formed from at least two atoms
Explanation:
A feature that distinguishes an elemental molecule and a compound molecule is whether the molecules are formed from at least two atoms.
An elemental molecule is a molecule that contains two or more of the same kind of elements.
A compound molecule contains two or more different kinds of molecules.
A molecule is a unit of a compound that can represent such a compound.
Therefore, what distinguishes an elemental molecule from a compound molecule is whether a molecule forms from at least two atoms.