AP BIOLOGY

Detailed explanation-1: -Natural Barriers Against Infection prevents invasion by microorganisms unless it is damaged (for example, by an injury, insect bite, or burn). Mucous membranes, such as the lining of the mouth, nose, and eyelids, are also effective barriers.

Detailed explanation-2: -NON SPECIFIC DEFENSES: Skin and Mucous membranes, antimicrobial chemicals, natural killer cells, phagocytosis, inflammation and fever.

Detailed explanation-3: -The skin and mucous membranes provide a nonspecific first line of defense against invaders entering through the skin or through openings into the body.

Detailed explanation-4: -Skin is a barrier that serves as one of the body’s first lines of defense against harmful microbes. Specialized immune cells within skin tissue help to fight invading organisms. Yet the skin hosts diverse communities of beneficial bacteria, collectively known as the skin microbiota.