Question

at the venous ends of the pulmonary capillaries...
multiple choice
the $pco_2$ is lower in the capillaries than in the alveoli
the $pco_2$ is higher in the capillaries than in the alveoli
the $pco_2$ is equal in the capillaries and in the alveoli
the $pco_2$ is higher at first in the capillaries than in the alveoli, and then it is lower in the alveoli than in the capillaries

Explanation:

Gas exchange occurs in the lungs. Carbon dioxide (\(PCO_2\)) diffuses from an area of higher concentration to an area of lower concentration. In the pulmonary capillaries, at the venous ends, after gas exchange has taken place, the \(PCO_2\) in the capillaries and alveoli reaches equilibrium.

Answer:

The \(PCO_2\) is equal in the capillaries and in the alveoli.