StringBuilder is a dynamic object that allows you to expand the number of characters in the string.
Multiple developers can work simultaneously with a single class in separate files.
In C#, Generics allow you to write a class or method that can work with any data type.
A sub class can only have one parent class but a subclass can implements or inherits one or more than one interfaces
An interface in c#, is a contract between itself and any class that implements it.