Answer and Explanation :
Three lines of immune systems are
- ADAPTIVE IMMUNITY : It comes into action when first and second line of defense are not working or in other word fail in their work
specific response in this adaptive immunity this is the third
line of defense effector T cells and B cells
- INNATE IMMUNITY : it come into into action when first line of defense fail to do his work
its components are
organ lymph nodes ,tonsils,
- BARRIERS AT BODY SURFACE : The barriers are used for the protection of body from infection there are mainly two types of infection physical infection and chemical infection these include skin, stomach tear etc