Which of the following statements are correct regarding monocytes? A. They are the most abundant white blood cells. B. They are classified as agranulocytes. C. They possess a kidney-shaped nucleus. D. They secrete histamine and serotonin. E. They are phagocytic cells that destroy foreign organisms. Choose the correct answer from the options below:

Step-by-step solution

Leucocytes are divided into granulocytes (neutrophils, eosinophils, and basophils) and agranulocytes (lymphocytes and monocytes). Thus, monocytes are agranulocytes (Statement B is correct). Neutrophils are the most abundant WBCs (60-65%), whereas monocytes comprise 6-8% of total WBCs (Statement A is incorrect). According to NCERT diagrams, monocytes have a kidney-shaped nucleus (Statement C is correct). Basophils secrete histamine, serotonin, and heparin, not monocytes (Statement D is incorrect). Neutrophils and mo