If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except
A) the pulmonary vein.
B) the trachea.
C) the right atrium.
D) the right ventricle.

Question

Quizplus · Accepted Answer

CO₂ exits the body through the respiratory system, which includes the trachea, bronchi, bronchioles, and alveoli. The pulmonary vein carries oxygenated blood from the lungs to the heart, so it would not be a pathway for CO₂ to exit the body. The right atrium and right ventricle are part of the circulatory system and are not involved in the exhalation of CO₂.

If a Molecule of CO₂ Released into the Blood in Your