Question

what is immunisation ? explain its mechanism?

Answer 1

the immune system is extremely important defense mechanism that can identify invalid organisms and destroy it . immunization prevents body by attaching  
disease firstly

Answer 2

The immune system and immunisation. ... The immune system is an extremely important defence mechanism that can identify an invading organism and destroy it. Immunisation prevents disease by enabling the body to more rapidly respond to attack and enhancing the immune response to a particular organism.