1. Approximately how many cases a year are heard by the Supreme Court. How is it decided which cases they choose to hear in the court.

In fact, the Court accepts 100-150 of the more than 7,000 cases that it is asked to review each year. Typically, the Court hears cases that have been decided in either an appropriate U.S. Court of Appeals or the highest Court in a given state (if the state court decided a Constitutional issue).

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.