Final answer:
The cell that is rarely found in the alveolus is the dust cell. The alveolar wall consists mainly of type I alveolar cells, which are squamous epithelial cells that make up the majority of the alveolar surface area.
Step-by-step explanation:
The cell that is rarely found in the alveolus is the Dust cell.
The alveolar wall consists mainly of type I alveolar cells which are squamous epithelial cells that make up the majority of the alveolar surface area.
Type II alveolar cells, also present in the alveolar wall, secrete pulmonary surfactant, while alveolar macrophages roam around the wall, removing debris and pathogens.