Inflammation produces four classical signs, including:

• A. Heat
• B. Redness
• C. Pain
• D. Swelling

Answer: (B)

Inflammation produces four classic signs because chemical signals and changes in blood flow alter the local tissue environment. Redness is one of these signs, arising from vasodilation of small blood vessels in the area. When vessels widen, more blood rushes to the site, giving the skin a red appearance (rubor). Mediators like histamine and nitric oxide drive this dilation, and the increased blood flow also contributes to the warmth often felt at the site. The other signs—heat, swelling, and pain—come from related processes: heat from the higher blood flow and metabolic activity, swelling from fluid leakage into the tissue, and pain from swelling and chemical mediators sensitizing nerve endings. So redness is indeed a correct and recognizable part of the inflammatory response.