What is active immunity?

Explanation

Acquired Immunity. Acquired immunity is the resistance to the diseases that an individual acquires during its lifetime. It has following properties :-
1. Specificity. It has the ability to differentiate between various foreign molecules.
2. Diversity. It can recognize a vast variety of foreign (non-self) molecules.
3. Memory. Immune system responds to first encounter, a specific foreign agent by forming antibodies. It retains the memory and if there is second attack by same antigen, `"microbe"//"foreign"` molecules) it evokes more quick and abundant immune response.
4. Discrimination between Self and Non-Self. It can recognise foreign (non-self) molecules and avoid response to self-antigens.