What is the main function of hemoglobin in red blood cells?

The primary function of hemoglobin in red blood cells is to transfer oxygen from the lungs to the rest of the body. Hemoglobin is a protein that binds to oxygen in the lungs, where oxygen concentration is high, and then carries it through the bloodstream to tissues and organs where oxygen is needed for cellular respiration and energy production. This essential role is crucial for maintaining proper physiological function and overall health, as all body cells require oxygen to produce energy.

In addition to transporting oxygen, hemoglobin also plays a role in the reversible binding of carbon dioxide, but its main function remains oxygen transport. Other options are not part of hemoglobin's primary roles. For instance, transporting glucose is handled through different mechanisms, such as blood delivry and absorption, and hemoglobin does not have a direct role in releasing toxins from the bloodstream.