Can someone explain polymorphsm to me? Or upload a program that include polymorphm. Need some examples.

Poly means many and morph means form or shape. It is the phenomenum of things being able to exist in different forms. If you have a Cat class which inherits from an Animal class and also implements an ISerializable interface then in your code you can create an instance of cat but refer to it as a Cat, an Animal or an ISerializable. Theres a lot more to it than that but that is the fundamental idea.