Respiratory epithelium structure analysis

Steps:

• Statement 1 is false: Goblet cells occur in pseudostratified columnar epithelium of bronchi, not between squamous epithelial cells, which line alveoli.
• Statement 2 is true: Smooth muscle layers surround bronchial walls, visible in cross-sections.
• Statement 3 is true: Cilia are characteristic of bronchial epithelium for mucociliary clearance, so the section can be bronchial.
• Only statements 2 and 3 are correct, matching option D.

Why D is correct:

• Bronchial epithelium is defined as pseudostratified ciliated columnar with goblet cells and underlying smooth muscle, confirming visibility of smooth muscle and cilia.

Why the others are wrong:

• A includes 1, but goblet cells are not in squamous epithelium.
• B includes 1, incorrectly placing goblet cells with squamous cells.
• C excludes 2, but smooth muscle is a key bronchial feature.

Final answer: D