Final answer:
Article III of the U.S. Constitution establishes the Judicial Branch and creates the Supreme Court as the highest court in the land, while also granting Congress the power to establish lower federal courts. The U.S. District Courts are responsible for handling federal cases, and the U.S. Court of Appeals hears appeals from the District Courts.
Step-by-step explanation:
Article III of the U.S. Constitution establishes the Judicial Branch and creates the Supreme Court as the highest court in the land. However, it also grants Congress the power to establish lower federal courts, including the U.S. District Courts and the U.S. Court of Appeals. These courts are part of the federal court system, which operates alongside state court systems. The U.S. District Courts are responsible for handling both criminal and civil cases at the federal level, while the U.S. Court of Appeals hears appeals from the District Courts.