Hello!
Elements are made up of atoms, and elements combine to make compounds. Compounds are made up of molecules, and molecules are made up of atoms.
Nitrogen is an element. It could be made up of one or many atoms. A mixture is made up of compounds, so it is not the answer.
Molecules and compounds are made up of different atoms and elements, but nitrogen is not a molecule or a compound.
There is such a thing as a nitrogen atom, though.
Therefore, your answer would be 2) Atom.
I hope this helps!
