Question

which of the following best describes what alveoli are?
they are the smallest tubes in the respiratory system.
they have a small amount of surface area.
they are found on the end of bronchioles.
they are comprised of millions of cells.
please select the best answer from the choices provided.
a
b
c
d

Explanation:

• Alveoli are tiny air - sacs at the end of bronchioles.
• The smallest tubes in the respiratory system are bronchioles, not alveoli (so A is wrong).
• Alveoli have a large surface area for gas exchange (so B is wrong).
• Alveoli are made of a single layer of squamous epithelial cells (not millions of cells in a complex multi - cell structure as D implies).

Answer:

C. They are found on the end of bronchioles.