Inheritance and Polymorphism are key concepts in object-oriented programming using Python.

Inheritance is the mechanism by which we can create a new class that is a modified version of an existing class. When a class is derived from an existing class, it inherits all the attributes, properties, and methods of the parent or base class.

This allows us to create a hierarchy of classes that represent more complex objects, with more specialized behaviors, as we move down the hierarchy. In Python, we use the keyword "class" to define a new class and using the keyword "super()", we can call the parent class constructor.

Polymorphism, on the other hand, refers to the ability of objects of different classes to be used interchangeably. Essentially, it means we can treat multiple objects as if they are the same type of object, even though they are instances of different classes.

Polymorphism allows us to write more generic and reusable code, as we don't have to write separate code for each individual class, but can instead write code that can be applied to multiple classes.

In Python, we can implement polymorphism by defining methods with the same name in different parent classes or child classes. This means we can call the same method on objects of different classes and get different behavior.

Overall, inheritance and polymorphism are powerful concepts that help us create more complex objects and write more reusable code, making our programs more efficient and easier to maintain.