Florida Basic Recruit Training Program High Liability (First Aid) Practice Exam

What is the function of white blood cells?

1. Transport oxygen

2. Fight infection

3. Clot blood

4. Transfer nutrients

The correct answer is: Fight infection

White blood cells, also known as leukocytes, play a critical role in the body's immune system. Their primary function is to defend against infections, whether they be bacterial, viral, or fungal. These cells are essential for detecting and responding to pathogens, identifying foreign substances, and coordinating an immune response that can involve both innate and adaptive immune mechanisms. When the body is invaded by pathogens, white blood cells are among the first responders. They can engulf and digest these invaders through a process called phagocytosis. Additionally, they produce antibodies that specifically target pathogens, facilitating their destruction and assisting in the body’s recovery processes. The other options detail functions that are performed by different components of the blood. Red blood cells are responsible for transporting oxygen to tissues, platelets aid in blood clotting, and plasma carries nutrients throughout the body. None of these functions pertains to the role of white blood cells, which distinctly focuses on fighting infections.