Final answer:
Urea is not excreted through the integumentary system.
Step-by-step explanation:
The integumentary system is responsible for protecting the body. While the system does play a role in excretion, the substance that is NOT excreted through the integumentary system is urea. Urea is a waste product produced by the liver as a result of protein metabolism and is primarily excreted through the urinary system.