Answer:
Article III of the Constitution, which establishes the Judicial Branch, leaves Congress significant discretion to determine the shape and structure of the federal judiciary.
Explaination:
The number of Supreme Court Justices is left no Congress-at times there have been as few as six, while the current number (nine, with one Chief Justices and Associate Justices) has only been in place since 1869. The Constitution also grants the Congress the power to establish courts inferior to the Supreme Court, and to that end the Congress has established the United States districts courts, which try most federal cases, and the United States occurs of appeals, which review appealed district court cases.