Final answer:
Rules of evidence are the guidelines that determine the admissibility of proof in legal proceedings. They have a crucial role in ensuring justice in both criminal and civil cases by setting different standards of proof required to establish guilt or liability.
Step-by-step explanation:
Rules of evidence govern whether, when, how, and why proof of a legal case can be placed before a judge or jury. These rules are essential in both criminal and civil trials to ensure a fair process. In a criminal case, the prosecution must prove guilt beyond a reasonable doubt, which is a higher standard compared to civil cases, where the plaintiff must prove the case beyond a preponderance of the evidence.
The principles of common law also play a significant role in shaping the rules of evidence, as they are based on previous judicial decisions and practices that have been established over time. During the trial, both sides present their evidence following these rules, and after closing arguments, the jury is instructed by the judge and proceeds with deliberations to reach a verdict.