Hemoglobin is primarily found in which type of cells?

Hemoglobin is primarily found in red blood cells, also known as erythrocytes. Red blood cells are specialized for the transportation of oxygen from the lungs to the body's tissues and for returning carbon dioxide from the tissues back to the lungs for exhalation. The presence of hemoglobin, a protein that contains iron, is critical for this function as it binds oxygen molecules, allowing red blood cells to efficiently carry oxygen throughout the circulatory system.

In contrast, white blood cells play a key role in immune response, platelets are involved in blood clotting, and plasma cells are specifically related to the production of antibodies. None of these cell types contain hemoglobin, which highlights the unique and vital function of red blood cells in the body.