help hurry

Which sentence includes a word that is used incorrectly?

The scientist explained that a molecule is made up of atoms.

The hermit lived in a remote region of the forest, so insulated that he did not see another human being for two years.

The heat was stifling, so I turned on the fan and opened all the windows.

The boy was so used to getting his way that he found it difficult to work in collaboration with others.