Final answer:
The trachea is kept open by a combination of C-shaped cartilage rings, elastic fibers, and the fibroelastic membrane.
Step-by-step explanation:
The trachea is kept open by a combination of C-shaped cartilage rings, elastic fibers, and the fibroelastic membrane. The C-shaped cartilage rings provide structural support and prevent the trachea from collapsing. The elastic fibers in the connective tissue allow the trachea to stretch and expand during inhalation and exhalation. The fibroelastic membrane, which consists of the trachealis muscle and elastic connective tissue, closes the posterior surface of the trachea, connecting the cartilage rings and providing flexibility.