What does the judicial branch do?

What does this answer mean?

The judicial branch reviews and explains laws and settles disagreements about them. USCIS accepts four answers: reviews laws, explains laws, resolves disputes (disagreements) about the law, or decides if a law goes against the Constitution.

Article III of the Constitution gives the judicial power to the Supreme Court and the lower federal courts. Courts hear cases, decide what a law means, and apply it to the facts in front of them.

One of the courts' most important powers is judicial review: deciding whether a law or an action by the government goes against the Constitution. The Supreme Court first struck down a federal law as unconstitutional in Marbury v. Madison, in 1803, in a decision written by Chief Justice John Marshall. Since then, the courts' power to review laws has been a key check on Congress and the president.

This is how the judicial branch fits into checks and balances: Congress writes laws, the president enforces them, and the courts explain them.

At the interview, a short answer is "explains laws."