Explanation:
Granulocytes are a type of white blood cells that contain granules in their cytoplasm. These granulocytes play a vital role in the immune system of the human body. There are three types of granulocytes present in human blood, namely neutrophils, eosinophils, and basophils.

Neutrophils are the most abundant granulocytes in human blood, accounting for about 60-70% of all white blood cells. They are also called polymorphonuclear leukocytes or PMNs due to their multilobed nucleus. Neutrophils play a crucial role in the innate immune response against bacterial and fungal infections. They are the first cells to arrive at the site of infection and engulf the invading microorganisms by a process called phagocytosis.

Monocytes are another type of white blood cells that are larger than neutrophils and have a single kidney-shaped nucleus. They differentiate into macrophages, which are also phagocytic cells that engulf and destroy invading pathogens. Monocytes account for about 2-8% of all white blood cells.

Basophils and eosinophils are less abundant than neutrophils and monocytes. Basophils account for less than 1% of all white blood cells and play a role in allergic reactions by releasing histamine. Eosinophils account for about 1-3% of all white blood cells and play a role in the immune response against parasites and allergic reactions.

In conclusion, the most abundant granulocytes in human blood are neutrophils, which play a crucial role in the innate immune response against bacterial and fungal infections.