Dominic's mistake lies in the statement regarding the state of matter for mixtures. The correct point should indicate that while some mixtures can exist with more than one state of matter, it is indeed possible for a mixture to consist of only one state of matter. Therefore, the entry "must have more than one state of matter" is incorrect. A mixture can be a homogeneous mixture (solution) or a heterogeneous mixture, and both can exist solely in one state, such as a solid, liquid, or gas.
Thus, the correct critique of Dominic's table would be:
"Although it is possible to have more than one state, it is also possible to have only one state."