Impact of Program Design Practice Test

A course management platform includes Course, Student, and Instructor classes. Course has a list of enrolled students and a Gradebook. The platform supports InPersonCourse and OnlineCourse, both extending Course. Each course type calculates participation differently, so both override a method like computeParticipationScore(student). The Gradebook calls computeParticipationScore through a Course reference when generating final grades. The team wants to add HybridCourse later without changing Gradebook. Considering the class design, how does polymorphism in the described classes benefit the program?

A game studio is building a level editor alongside its game, so designers can add new enemies without changing core engine code. The class design includes GameCharacter, Enemy, and Level. GameCharacter stores private position and health and provides move and takeDamage methods. Enemy extends GameCharacter and adds a method chooseAction(Level level). Specific enemies like SlimeEnemy and BossEnemy extend Enemy and override chooseAction differently. Level keeps a list of Enemy objects and calls chooseAction on each enemy during update(), without checking the enemy’s exact class. This is polymorphism: Level interacts with the Enemy type, and each subclass decides its behavior. Encapsulation prevents Level from directly changing health, so damage must go through takeDamage, which enforces nonnegative health. The team finds this design easier to maintain because adding a new enemy only requires a new subclass; Level’s update loop stays the same. It also improves readability by keeping enemy logic inside enemy classes rather than in Level. Performance remains manageable because the update loop avoids a long chain of type checks, which would grow as more enemy types are added. Based on the scenario, how does polymorphism in the described classes benefit the program?