What component of blood is responsible for fighting infection?

White blood cells, also known as leukocytes, play a crucial role in the immune system by defending the body against infections. These cells are equipped to identify and eliminate pathogens such as bacteria, viruses, and other foreign substances that can cause illness. There are various types of white blood cells, including lymphocytes, neutrophils, and monocytes, each specializing in different aspects of the immune response.

In contrast, other components of blood serve different functions. Plasma, for example, is the liquid portion of blood that carries nutrients, hormones, and waste products, but does not actively fight infections. Red blood cells are responsible for transporting oxygen from the lungs to the body's tissues and carrying carbon dioxide back to the lungs, while platelets are involved in blood clotting. Thus, the specific role of white blood cells in immunological defense makes them the key component responsible for fighting infection.