What are the most numerous calls in the blood?

The most numerous cells in the blood are red blood cells (RBCs), or erythrocytes, which are responsible for transporting oxygen from the lungs to tissues and returning carbon dioxide for exhalation. In a typical healthy adult, there are about 4.5 to 6 million red blood cells per microliter of blood. In comparison, white blood cells (leukocytes) and platelets are present in much smaller quantities, with white blood cells numbering around 4,000 to 11,000 per microliter and platelets around 150,000 to 450,000 per microliter.