The answer is Erythrocytes.
There are about 4,000,000 - 6,000,000 erythrocytes per microliter of the blood.
There are about 5,000 - 10,000 leukocytes per microliter of the blood.
There are about 150,000 - 400,000 thrombocytes per microliter of the blood.
Therefore, the most abundant cells in the blood are erythrocytes.
