Question

How does oxygen enter the bloodstream?

a) It passes through the cell membranes of the esophagus.
b) It does not enter the bloodstream.
c) It passes through the cell membranes of the bronchial tubes.
d) It passes through the cell membranes of the alveoli.

Answer 1

d-it passes through the cell membranes of the alveoli

Step-by-step explanation:

once the oxygen has passed through the bronchial tubes it will go through the thin walls of the alveoli, and since the walls are so thin the oxygen can go through and enter the bloodstream.