Which of the following is a primary function of the integumentary system?

• A. Protection
• B. Digestion
• C. Blood filtration
• D. Hormone production

Answer: (A)

The main idea here is that the integumentary system’s primary job is to protect the body. The skin acts as a sturdy barrier that shields internal tissues from mechanical injury, infections, and chemicals, while also helping prevent water loss. It also blocks a significant amount of UV radiation and contains immune cells that help detect and respond to invaders. Temperature regulation and sensing are important supporting roles, but the core function is protection.

Digestion, blood filtration, and hormone production belong to other body systems, so they’re not the primary purposes of the skin. (Note: the skin does contribute to vitamin D production when exposed to sunlight, which indirectly relates to hormonal regulation, but that isn’t its main role.)