What legislation organized the Supreme Court with one chief justice and five associate justices?

The Judiciary Act of 1789 is significant as it established the structure and jurisdiction of the federal court system, including the Supreme Court. This legislation specifically organized the Supreme Court to consist of one chief justice and five associate justices, a framework that laid the foundation for the federal judiciary in the United States.

It is important to understand that this Act not only defined the composition of the Supreme Court but also set forth the authority and responsibilities of lower federal courts. The establishment of the judicial system was a key part of the early efforts to implement the Constitution and ensure the rule of law in the new nation.

The other options refer to acts or amendments that do not accurately describe the initial organization of the Supreme Court as prescribed by the Judiciary Act of 1789. The Judiciary Reform Act and the Federal Court Organization Act are not recognized pieces of legislation that address the original structure of the Supreme Court, and the Constitutional Amendments Act does not pertain specifically to the organization of the judiciary. Thus, the Judiciary Act of 1789 is the correct answer to this question.