Explain the difference between composition and aggregation in Object-Oriented Programming, and provide examples of when each is appropriate.

Composition and aggregation both establish relationships between classes, but they differ in ownership and lifecycle management. Composition implies strong ownership, where the lifetime of the contained object is dependent on the containing object. Aggregation implies a weaker relationship, where the contained object can exist independently. For example, a Car class composed of Engine and Wheel objects demonstrates composition, while a Library class aggregating Book objects showcases aggregation.