Question

which first line of defense is a natural barrier that works against pathogens?
skin
inflammation
t cells
tears

Explanation:

The first line of defense against pathogens includes natural barriers. Skin is a physical natural barrier that prevents pathogens from entering the body. Inflammation is a second - line defense response. T cells are part of the third - line (adaptive) immune response. Tears have some antimicrobial properties but skin is the primary natural barrier as a first - line defense.

Answer:

A. skin