Question

how does the system of federalism limit the power of the government?
by separating powers among the three branches of the national government
by making the state governments superior to the national government
by allowing the national government to define its own powers
by giving only some powers to the central government

Explanation:

Federalism divides powers between levels of government. The central government gets specific powers (like national defense), while states have others (like local laws). This limits the central government's power as it doesn't have all powers. Separating powers among national branches is separation of powers (not federalism). State governments aren't superior in federalism (they have their own spheres). National government can't define all its powers alone (states have input).

Answer:

by giving only some powers to the central government