Answer:
establishment of the number of judges that sit on the Supreme Court
Step-by-step explanation:
Article III, Section 1 of the United States Constitution establishes the following:
1. The Judicial power of the US is vested in the supreme court.
2. Congress can form or establish lower
3. Judges of the United States will maintain their position during good behavior
Hence, in this case, the correct answer to the question is that the "establishment of the number of judges that sit on the Supreme Court, " because it is not a part of the United States Constitution under Article III Section I