Which of the following is an example of a physiological defense mechanism of the body against infection?

• A. Fever
• B. Inflammation
• C. Hypertension
• D. Edema

Answer: (B)

Inflammation is the body's immediate, localized defense against infection. When pathogens invade tissue, chemical signals trigger blood vessels to widen and become more permeable, bringing immune cells such as neutrophils and macrophages to the site. This response helps contain the infection, neutralize pathogens, and kick off tissue repair. The classic signs—redness, heat, swelling, and pain—reflect these protective processes at work. Edema you see is a common result of the vascular changes in inflammation, not a separate defense mechanism. Fever is also a protective systemic response, but it’s broader and not as directly tied to the tissue-level defense being illustrated here. Hypertension isn’t a defensive response to infection.