What is the primary function of leukocytes in the human body?

• A. Fight allergies
• B. Fight infections
• C. Regulate body temperature
• D. Produce hormones

Answer: (B)

Leukocytes, commonly known as white blood cells, play a crucial role in the immune system, serving primarily to fight infections. They are the body's primary defense mechanism against pathogens such as bacteria, viruses, fungi, and parasites. When an infection occurs, leukocytes identify and attack these foreign invaders, coordinating the immune response to eliminate them and prevent the spread of disease.

Different types of leukocytes, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, have specialized functions in identifying and eliminating pathogens. For example, neutrophils are often the first responders to sites of infection, while lymphocytes are integral to adaptive immunity, with roles in both recognizing specific pathogens and remembering them for faster response in future encounters.

Other options, such as fighting allergies, regulating body temperature, and producing hormones, represent functions carried out by different systems or cell types within the body. While some leukocytes can indeed be involved in allergic responses, this is not their primary function. Therefore, the core function of leukocytes firmly rests on their critical role in fighting infections, protecting the body against illness and disease.