If a molecule of carbon dioxide enters the blood in your left toe and is exhaled from your nose, it must pass through all of the following EXCEPT ________.
A) the pulmonary vein
B) an alveolus
C) the trachea
D) the right atrium
E) the right ventricle

Question

Quizplus · Accepted Answer

The pulmonary vein carries oxygenated blood from the lungs back to the left side of the heart, which is not a path carbon dioxide follows when moving from the body to be exhaled. Carbon dioxide travels from the body's tissues to the heart, then to the lungs to be exhaled, bypassing the pulmonary vein in this direction.

If a Molecule of Carbon Dioxide Enters the Blood in Your