Q.Name and explain the type of barriers which involve macrophages.

Innate immunity is the natural, non-specific resistance to infection an individual is born with, active against a broad range of pathogens rather than one specific antigen. It operates through four layers of defence: anatomical barriers (skin and mucus membranes that physically block or trap microbes), physiological barriers (body temperature, gastric acidity, and chemical mediators such as lysozyme, interferons and complement that chemically disable pathogens), phagocytic barriers (monocytes, neutrophils and macrophages that engulf and digest microbes), and inflammatory barriers (vascular leakage carrying …