1. The problem involves understanding Prolog queries based on given facts (Example 28). We need to determine what Prolog would return for each query. 2. Prolog queries return true/false or variable bindings based on facts and rules defined. The queries ask about instructors and enrollments. 3. For query a) ?instructor(chan,math273): Prolog checks if 'chan' is an instructor for 'math273'. If the fact exists, it returns true; otherwise false. 4. For query b) ?instructor(patel,cs301): Prolog checks if 'patel' is an instructor for 'cs301'. Returns true or false accordingly. 5. For query c) ?enrolled(X,cs301): Prolog returns all X such that X is enrolled in 'cs301'. It lists all students enrolled. 6. For query d) ?enrolled(kiko,Y): Prolog returns all Y such that 'kiko' is enrolled in course Y. 7. For query e) ?teaches(grossman,Y): Prolog returns all Y such that 'grossman' teaches course Y. 8. Without the exact facts from Example 28, we cannot provide exact answers, but the process is to match queries against facts and return true/false or variable bindings. Final answer: Prolog returns true/false for instructor queries and lists of courses or students for enrolled and teaches queries based on the facts in Example 28.