What does the term 'memory' of the immune system mean?

Assertion : Principle of vaccination is based on the property of 'memory' of the immune system. Reason : In vaccination a preparation of antigenic protein of pathogens or inactivated/ weakened pathogen are introduced into the body.

Differentiate between the roles of B-lymphocytes and T-lymphocytes in generating immune responses. OR Principle of vaccination is bassed on the property of "memory" of the immune system. Taking one suitable example, justify the statement.

Life of the memory cells of immune system is

Give reasons : (ii) Vaccination is based on the property of memory of immune system.

What does the term 'Frugivorous' mean ?

Life of the effector cells of immune system is

What are the barriers of innate immunity?

Active immunity means

Active immunity means