3. What it is
If there are certain properties or
methods you want to use in class, you
can get them from an existing class.
4. How it works
When you make a new class using
inheritance, the new class is called a
derived class.
5. Why we use it
The beauty in a derived class is that you
can always keep it up to date with the
super class because any changes you
make to the super class will be
automatically applied to the derived
class.
Another reason derived classes are
beautiful is because they can have all of
the super class properties and have
their own properties and methods.