Which option correctly identifies the body feature affected by pH?

• A. Teeth, eyelashes, eyebrows, ears, and nose
• B. Cosmetic products
• C. Health status
• D. Hair, skin, and nails

Answer: (D)

pH governs the acidity balance on the body's surface, and the tissues most directly shaped by that balance are the keratinized parts: hair, skin, and nails. The skin’s acid mantle, normally slightly acidic, helps maintain moisture and barrier function; products with an out-of-range pH can disrupt this barrier, leading to irritation, dryness, and damage to the cuticles and nail plates, or to rough, frizzy hair. Because these tissues rely on a stable surface pH to stay healthy and look right, hair, skin, and nails are the body features most affected by pH. Teeth can be influenced by oral pH, but that’s a different environment; cosmetic products aren’t body features themselves; health status is a condition, not a feature. So the option pointing to hair, skin, and nails best fits the concept.