Final answer:
The Senate confirms the appointment of a Supreme Court Justice.
Step-by-step explanation:
The group that confirms the appointment of a Supreme Court Justice is the Senate. The President nominates a candidate for the vacancy, and the Senate then holds confirmation hearings to evaluate the nominee's qualifications. If the Senate approves the nominee with a majority vote, they will be confirmed as a Supreme Court Justice.
Learn more about Appointment of Supreme Court Justices