Hemoglobin functions by:

A) dissolving in blood plasma to create the partial pressure of carbon dioxide.
B) binding to oxygen that is absorbed in the lungs and transporting it to the tissues.
C) absorbing hydrogen ions in the blood in order to maintain acid-base balance.
D) transporting red blood cells throughout the body to ensure adequate oxygenation.

Answer: B) binding to oxygen that is absorbed in the lungs and transporting it to the tissues.