Answer 1

OOP stands for object oriented programming. it is a methodology to design a program using classes and objects. (collection of objects is called class)
there are 7 OOPs concepts
1. Polymorphism - performing one task in different ways.
2. Abstraction - hiding internal details and showing only functionality.
3. Encapsulation - Wrapping code and data together into a single unit.
4. Inheritance - child inheriting properties of parent class.
5. Association - a relationship ship where all objects have there own life cycle.
6. Aggregation - a specialized form of association.
7. Composition - a specialized form of aggregation.