Final answer:
State courts handle most cases, but federal courts hear cases involving federal questions or controversies between states.
Step-by-step explanation:
Most court cases in the United States are decided in state courts, and a state case is more likely to be heard by the federal courts when it involves a federal question. Federal courts take cases related to issues such as constitutionality, federal laws, or controversies involving multiple states. On the other hand, state courts handle a wide array of cases including most crimes, civil matters, family law, and contract disputes. State and federal courts can both hear civil and criminal law matters, and cases may transition from state to federal courts through appeal if they involve federal laws or constitutional issues.