Which of the following is NOT a responsibility of the executive branch?

The correct answer highlights an essential distinction in the functions of government branches defined by the United States Constitution. The executive branch is responsible for enforcing laws and carrying out government functions, which includes appointing federal judges, making treaties, and submitting bills to Congress for legislative consideration.

Conducting court trials is exclusively the responsibility of the judicial branch. This branch is tasked with interpreting laws and ensuring justice is administered through the court system. Therefore, while the executive may influence the judicial branch through appointments and other mechanisms, the actual conduct of trials is not within its purview, making it the correct choice in this context. Understanding this division of responsibilities is crucial for grasping the overall structure of the U.S. government.