About two-thirds of waste carbon dioxide is carried back to the lungs in higher animals by
A) by red blood cells on the empty hemes.
B) by dissolved in blood plasma as bicarbonate and hydrogen ions.
C) by dissolved in lymph in lymph ducts.
D) by on myoglobins.
E) None of the choices are correct

Question

Quizplus · Accepted Answer

Waste carbon dioxide in higher animals is mostly converted to bicarbonate and hydrogen ions by the enzyme carbonic anhydrase in red blood cells. These ions are then transported in blood plasma to the lungs, where they are converted back to carbon dioxide for exhalation. Only a small amount of carbon dioxide binds to hemoglobin on red blood cells. Lymph does not play a significant role in the transport of waste carbon dioxide.

About Two-Thirds of Waste Carbon Dioxide Is Carried Back to the Lungs