Name and give an example of each(i) The disease causing factors within body.(ii) The non-cellular disease causing microorganism.(iii) The substance introduced in body to confer immunity against subsequent infection.
(i) Intrinsic factors, e.g. excessive weight, hormonal imbalance. (ii) Virus, e.g. AIDS, influenza. (iii) Weakened or killed antigens introduced through vaccination confer immunity against specific infections, e.g. polio vaccine.