Red blood cells are primarily responsible for:

• A. Storing nutrients in the body
• B. Transporting oxygen and carbon dioxide
• C. Regulating blood pressure
• D. Producing white blood cells

Answer: (B)

Red blood cells, or erythrocytes, play a crucial role in the circulatory system by primarily transporting oxygen from the lungs to the tissues and carrying carbon dioxide from the tissues back to the lungs for expulsion. This function is facilitated by the protein hemoglobin, which binds oxygen and carbon dioxide. The ability of red blood cells to efficiently deliver oxygen is essential for cellular metabolism and overall physiological function, as all cells require oxygen to produce energy.

While other blood components are involved in various functions, such as storing nutrients, regulating blood pressure, and producing white blood cells, these tasks are not the primary functions of red blood cells. For example, plasma proteins are more involved in nutrient transport, the vascular system plays a significant role in blood pressure regulation, and the bone marrow is where white blood cells are produced. Thus, the unique and pivotal role of red blood cells in oxygen and carbon dioxide transport solidifies option B as the correct answer.