What is a key function of the integumentary system?

The integumentary system plays a crucial role in regulating body temperature, making this choice the correct answer. This system includes the skin, hair, nails, and associated glands, all of which help maintain the body's temperature within a normal range.

When the body gets too hot, sweat glands in the skin produce sweat, which evaporates from the surface of the skin and cools the body. Additionally, blood vessels in the skin can dilate (widen) to increase blood flow, facilitating heat loss. Conversely, when the body is cold, these blood vessels constrict (narrow) to retain heat.

The other options do not accurately represent the primary functions of the integumentary system. While the integumentary system does provide some protective barriers, it does not directly absorb nutrients, produce hormones significantly compared to glands such as the endocrine system, nor transport oxygen, which is the function of the circulatory and respiratory systems. Therefore, the regulation of body temperature remains a fundamental and distinct function of the integumentary system.