Powers of Congress/States Denied by Constitution

Question

What two powers is Congress denied in the Constitution?

What two powers are the States' denied in the Constitution?

Answer 1

Congress cannot take territory from a state without the state's approval.  No tax may be imposed on exports from any state.

The "privileges and immunities" clause prohibits state governments from discriminating against citizens of other states in favor of resident citizens.   A state may not enter into a treaty.