What component of blood is responsible for carrying oxygen and nourishment to cells?

Red blood cells play a critical role in the transport of oxygen and nourishment to cells throughout the body. They contain hemoglobin, a protein that binds to oxygen in the lungs and releases it in the tissues. This process is essential for cellular respiration, which provides the energy cells need to function.

In addition to oxygen transport, red blood cells can also transport some carbon dioxide back to the lungs for exhalation, although the primary focus here is on their role in oxygen delivery. The nourishment referred to in the question primarily involves nutrients, which are usually carried in the plasma as part of the blood's liquid component. However, the specific dedication of red blood cells to carrying oxygen makes them fundamentally essential for this role.

While plasma facilitates various functions, including the transport of nutrients and waste products, it does not directly carry oxygen to cells. White blood cells are primarily involved in immune response, and platelets are key to blood clotting processes. Therefore, the distinct function of red blood cells in oxygen transport is what makes them the correct answer.