What is one function of white blood cells?

White blood cells, also known as leukocytes, play a crucial role in the body's immune system, and one of their primary functions is to fight diseases. They are responsible for identifying and responding to pathogens, such as bacteria, viruses, and other foreign invaders. When an infection occurs, white blood cells are activated and can directly attack these pathogens or produce antibodies that target them for destruction. This defense mechanism is vital for maintaining the body’s health and preventing illness.

In contrast, other functions mentioned in the choices relate to different components of the blood and bodily systems: transporting oxygen is primarily a function of red blood cells; creating blood clots involves platelets; and filtering waste products is the job of organs like the kidneys. Understanding the specific roles of different blood components helps clarify the importance of white blood cells in the immune response.