Final answer:
The most numerous leukocyte capable of phagocytosis is the neutrophil.
Step-by-step explanation:
The most numerous leukocyte that can undergo phagocytosis of harmful microbes is the neutrophil. Neutrophils are a type of white blood cell that play a crucial role in the body's immune response. They possess the ability to engulf and destroy bacteria and other pathogens through the process of phagocytosis.
Learn more about Neutrophils and phagocytosis