Sub class is part of a class luxury. But it differs in that the subcomponents will not be removed from the core component. Because if the sub components, core components, it will lose, as that class.
Subclass as part of the core classes. But the difference is that components can not be removed from the main part. If you take out a major component subassembly, it will lose the properties of a class.
Subclass is part of the core classes. But unlike sub components cannot be brought out of the main components. If the component subsystems, and the main components, it will lose the properties of a class.