Answer:
Health Occupations Students of America
Explanation:
HOSA promotes career opportunities in the healthcare industry, which enhances the delivery of quality health services to all people.
A city's population density would decrease (most likely) due to the fact that people would most likely spread out.
I'm thinking Lack of Motivation. I'm going to double check though for you.
The two cell layers being referred from the question are a layer of alveolar cells and layer of endothelial cells. Gases must diffuse to these layers to proceed to the plasma. The layer of alveolar cells make up the alveolar wall while the layer endothelial cells consist the capillary wall.