ASCP Medical Laboratory Technician (MLT) Practice Exam

The primary function of red blood cells is indeed to transport oxygen from the lungs to the body's tissues. This is achieved through a protein called hemoglobin, which binds to oxygen molecules in the lungs and releases them as the cells travel through the bloodstream to the tissues. This oxygen transport is critical for cellular respiration, the process by which cells generate energy.

In addition to their primary function, red blood cells also play a role in transporting carbon dioxide, a waste product of metabolism, from the body's tissues back to the lungs for exhalation. This dual role is essential for maintaining the proper functioning of the body's respiratory and metabolic systems.

Other options, while involving different aspects of physiology, do not pertain to the primary role of red blood cells. For instance, the immune response is primarily managed by white blood cells, hormones are produced by endocrine glands, and body temperature regulation is maintained through various mechanisms involving the nervous and endocrine systems, rather than red blood cells.