Final answer:
Federal trials in the district courts are overseen by a single judge, and appeals in the circuit courts are heard by a panel of three judges. The district courts conduct trials, while the circuit courts review decisions from the district courts.
Step-by-step explanation:
At the federal level, trials in the district courts are before a single judge, and appeals are heard by a panel of three judges.
The United States is divided into ninety-four federal judicial districts, each with its own district court. These courts serve as the trial courts of the national system, where federal cases are tried by a single judge, witness testimonies are heard, and evidence is presented. Cases are often decided by a jury, although in some instances, they may be decided solely by the judge.
When it comes to appeals, the U.S. is served by thirteen courts of appeals, commonly referred to as circuit courts. Every appellate case is overseen by a rotating panel of three judges. These courts do not conduct trials but review the decisions made by district courts in their jurisdiction. With 179 judges authorized by Congress, they act as intermediate appellate courts, with their rulings subject to further review by the U.S. Supreme Court under certain circumstances.