Which system includes the skin, hair, and nails?

Which system includes the skin, hair, and nails?

• A. Integumentary
• B. Nervous
• C. Endocrine
• D. Circulatory

Answer: (A)

The main idea here is that skin, hair, and nails are all parts of the body's outer covering, which is the integumentary system. The skin is the largest organ and serves as a protective barrier, helps regulate temperature, and allows sensation. Hair and nails are skin-derived structures that support protection and other functions, making them natural components of this system. The nervous system, by contrast, centers on the brain, spinal cord, and nerves and handles signaling and control throughout the body. The endocrine system consists of glands that release hormones, coordinating many body processes, while the circulatory system moves blood through vessels and the heart. Since none of these three systems are defined by including skin, hair, and nails, the integumentary system is the correct choice.

The main idea here is that skin, hair, and nails are all parts of the body's outer covering, which is the integumentary system. The skin is the largest organ and serves as a protective barrier, helps regulate temperature, and allows sensation. Hair and nails are skin-derived structures that support protection and other functions, making them natural components of this system.

The nervous system, by contrast, centers on the brain, spinal cord, and nerves and handles signaling and control throughout the body. The endocrine system consists of glands that release hormones, coordinating many body processes, while the circulatory system moves blood through vessels and the heart. Since none of these three systems are defined by including skin, hair, and nails, the integumentary system is the correct choice.