A Rule-Based System is a type of artificial intelligence that uses a set of predefined rules to make decisions or solve problems. These rules are typically expressed in the form of "if-then" statements, allowing the system to evaluate conditions and take appropriate actions based on the input it receives. This approach is commonly used in expert systems, where the goal is to mimic human decision-making in specific domains. These systems rely on a knowledge base, which contains the rules and facts relevant to the problem area. When a user inputs data, the system processes it against the rules in the knowledge base, drawing conclusions or providing recommendations. Examples of applications include medical diagnosis systems and customer support chatbots, which utilize artificial intelligence to enhance their functionality.