Question

which organ system is not lined with mucus membrane?
urogenital
digestive
respiratory
cardiovascular

Explanation:

Mucus membranes line body cavities that open to the outside. The urogenital, digestive, and respiratory systems have openings to the external environment and are lined with mucus membranes. The cardiovascular system is a closed - loop system and is not lined with mucus membrane.

Answer:

D. Cardiovascular