Which of the following is NOT a responsibility of the grand jury?

The reason "conducting trials" is not a responsibility of the grand jury is grounded in the specific role that grand juries play within the judicial system. A grand jury is primarily tasked with reviewing evidence presented by the prosecution to determine whether there is sufficient cause to issue an indictment against a suspect, which is a formal charge.

Unlike a trial jury, which is responsible for weighing evidence, listening to witness testimonies, and ultimately determining the guilt or innocence of a defendant during a trial, a grand jury does not engage in these proceedings. Instead, it operates in a more preliminary capacity, focusing on the decision of whether to charge someone with a crime based on the evidence presented.

By fulfilling its responsibilities of deliberating evidence and issuing indictments, the grand jury protects against unfounded charges while allowing the prosecutorial process to move forward when there is sufficient basis to believe that a crime has occurred. The role of examining witness credibility typically falls within the purview of a trial jury or during court proceedings, where the fact-finding aspects of the case are fully addressed.