ALTERED IMMUNE RESPONSE: Definition: 1) Define/explain immunity: Immunity is a type of resistance that is provided by the host’s body. When any foreign body or antigen enters the body, the host’s immune system is activated and fights against the antigen and produces antibodies, which is called immunity. 2) Define/explain allergy (Define allergy): Allergy is an inappropriate and harmful immune response of the body’s immune system against a harmless substance. 3)