In what way do red blood cells assist with gas exchange?

Red blood cells are essential for gas exchange in the body primarily due to their role in transporting oxygen and carbon dioxide. Hemoglobin, a protein found in red blood cells, binds oxygen in the lungs where it is abundant and transports it to tissues throughout the body where oxygen is required for cellular respiration. Once the oxygen is delivered, the red blood cells pick up carbon dioxide, a waste product produced by cells during metabolism, and transport it back to the lungs where it can be exhaled. This dual function of carrying oxygen to the body's tissues and facilitating the removal of carbon dioxide is crucial for maintaining the body's overall gas balance and supporting cellular functions. Thus, the correct choice highlights the primary and vital function of red blood cells in gas exchange.