The branches of the federal government are: Executive, Legislative, and Judicial Branches.
The Executive Branch: Can check the power of the Judicial Branch by nominating judges and can check the power of the Legislative Branch by applying a veto on a congressional legislation.
The Judicial Branch: Can check the power of the Executive Branch by declaring an presidential act unconstitutional and check the power of the legislative branch by declaring a law unconstitutional.
The Legislative Branch: Can check the Executive Branch by approving or not presidential nominations and controlling the budget and check the power of the judicial branch by confirming the Presidents nominations to Courts, impeach judges and remove them from office.