Which organ system is comprised of the skin, hair, and nails?

The integumentary system is specifically designed to serve several vital functions for the body. It includes the skin, hair, and nails, which collectively play critical roles in protecting the body from external threats like pathogens, preventing water loss, and regulating temperature. The skin acts as a barrier, acting as the first line of defense against environmental hazards. Hair can provide some insulation and also helps in the sensation of touch, while nails protect the tips of fingers and toes and also assist in grasping objects.

In addition to protection, the integumentary system is involved in the synthesis of vitamin D when the skin is exposed to sunlight, which is crucial for calcium metabolism and overall health. This system also contains sensory receptors that help detect touch, pain, and temperature, contributing to the body's ability to respond to its environment.

This foundational knowledge of the integumentary system highlights why this choice is the correct answer, given its critical components and functions, distinguishing it clearly from the other organ systems listed.