> at the end of the day, it inherits the attributes, methods and behavior, of the "muscle" class Really, it inherits from the general "biological system" class

> at the end of the day, it inherits the attributes, methods and behavior, of the "muscle" class Really, it inherits from the general "biological system" class, of which "muscle" is the common subclass referenced, since it's the one most people have familiarity in utilizing. The differentiation of "muscle" from other "biological system" classes is entirely unrelated to the "use-it-or-lose-it" feature, however, and your subclassing is inappropriate. While this seems like being pedantic, I'd argue it's important to know when we're using a member to exemplify a class versus when we're talking about the definition of a class. The same use-it-or-lose-it applies to everything from lung capacity to stomach size to hormone production by organs, and is a good principle to know about how biology works. The emphasis on "muscle" as the class (rather than an exemplifying member) hides this underlying truth about all biological systems -- that they dynamically adapt to efficiency.