1. A subclass or child typically can do more (in terms of methods) than the superclass or parent 2. If a class contains one or more abstract methods, an instance of the class cannot be created. 3. Using extends is an example of a "is a" relationship. 1. A subclass or child typically can do more (in terms of methods) than the superclass or parent 2. If a class contains one or more abstract methods, an instance of the class cannot be created. 3. Using extends is an example of a "is a" relationship