What is the most common type of leukocyte in a healthy adult?

• A. Eosinophils
• B. Lymphocytes
• C. Monocytes
• D. Neutrophils

Answer: (D)

Verified step by step guidance

1. Understand that leukocytes, or white blood cells, are a crucial part of the immune system, responsible for defending the body against infections and foreign invaders.
2. Recognize the different types of leukocytes: neutrophils, eosinophils, lymphocytes, monocytes, and basophils, each with specific roles in the immune response.
3. Identify that neutrophils are the most abundant type of leukocyte in the bloodstream of a healthy adult, typically comprising about 50-70% of the total white blood cell count.
4. Learn that neutrophils are the first responders to microbial infection; their primary function is to engulf and destroy bacteria and fungi through a process called phagocytosis.
5. Remember that the high prevalence of neutrophils in the blood is due to their critical role in the innate immune response, providing a rapid reaction to infection.