Final answer:
The major functions of the integumentary system, which includes the skin, hair, and nails, are temperature control and protection of the body, thus E) integumentary is the correct answer.
Step-by-step explanation:
The major functions of the integumentary system are temperature control and protection of the body from the external environmental hazards. The integumentary system includes the skin, hair, and nails, and is the body's largest organ system.
It provides a protective covering for the body, senses the environment, and assists in maintaining homeostasis. The skin serves as a barrier protecting internal structures and fluids from harmful microorganisms and other environmental toxins.
Additionally, the integumentary system works together with other organ systems like the cardiovascular system to regulate homeostasis in the human body. Thus, the answer to the student's question is E) integumentary.