Red blood cells (RBCs), or erythrocytes, play a crucial role in the body by transporting oxygen from the lungs to various tissues and organs. They contain hemoglobin, a protein that binds to oxygen, allowing efficient delivery. RBCs also aid in the removal of carbon dioxide, a metabolic waste product, transporting it back to the lungs for exhalation. These cells are essential for maintaining the body's oxygen levels and are crucial for overall metabolic processes. Their lifespan is typically around 120 days, after which they are recycled in the spleen and liver. Proper function of RBCs is vital for overall health.