Q. Which is not made up of smooth muscle? 1. Trachea 2. Primary bronchus 3. Segmental bronchus 4. Alveoli
It's not the trachea... the tracheal muscle (smooth muscle) is continuous from the hyaline cartilage and are both making up structures of the trachea. The correct answer is alveoli. It's made up solely by a single layer of simple squamous epithelium. Sorry my dear.
The trachea is surrounded by rings of hyaline cartilage; these rings are incomplete and C-shaped. In front of the rings lies connective tissue and skin.