Answer: (2)
The three main groups of blood cells are erythrocytes(RBC), leucocytes(WBC), and platelets. Leukocytes are often known as white blood cells, due to lack of haemoglobin, they are colourless. WBC are classified into two groups they are
- Granulocytes
- Non-granulocytes
The lifetime of white blood cells in the lymph system is 13 to 20 days, and the existence of white blood cells is lost in the lymph system.