Final answer:
The vast majority of cases that reach the Supreme Court come from lower courts such as the US Court of Appeals or state Supreme Courts. The Court selects cases based on a writ of certiorari and only takes cases involving constitutional questions or differing interpretations of a law.
Step-by-step explanation:
The vast majority of cases that reach the Supreme Court come from other lower courts, such as the US Court of Appeals or state Supreme Courts. These cases are selected based on a writ of certiorari, which is a request for review by the Supreme Court. The Court only takes cases that involve constitutional questions or differing interpretations of a law. If the writ of certiorari is not granted, the lower court's decision stands. Four out of the nine justices must agree to grant certiorari.
Additionally, cases heard by the Supreme Court can come from state supreme courts when there is a substantive federal question involved in the case. However, it is important to note that the Supreme Court hears a relatively small number of cases compared to the state courts, as the majority of cases are handled at the state level.