Something studied on the molecular level is the water.
Explanation:
Water is a molecule formed by two hydrogen atoms and one oxygen atom, whose chemical representation is H₂O. It is a molecule whose polarity makes it a universal solvent of other polar molecules.
The molecular level corresponds to the level of organization where two or more atoms unite to form molecules or substances, united by chemical bonds. H₂O is studied at this level due to its chemical structure.
With respect to other options:
<u><em>Hydrogen and oxygen</em></u><em> are atoms, and correspond to the level of atomic organization.</em>
<u><em>Protons</em></u><em> are particles that are part of an atom, and correspond to the subatomic level.</em>
