Final answer:
The structure of the lower federal court system is established by Congress. The system consists of district courts, circuit courts, and the U.S. Supreme Court.
Step-by-step explanation:
The structure of the lower federal court system is established by Congress, as stated in the Constitution.
The first session of the first U.S. Congress laid the framework for today's federal judicial system, established in the Judiciary Act of 1789. At the lowest level are the district courts, where federal cases are tried. A losing party may appeal to the circuit courts, and further appeal can be made to the U.S. Supreme Court.
The three-tiered structure of the federal court system, consisting of district courts, circuit courts, and the U.S. Supreme Court, provides a clear-cut hierarchy for the federal judiciary.