Which of the following is NOT a type of white blood cell?

Platelets are not classified as a type of white blood cell. They are actually small cell fragments essential for blood clotting and the prevention of bleeding. In a healthy immune system, white blood cells, or leukocytes, play a crucial role in fighting infections and providing immunity.

Basophils, eosinophils, and lymphocytes are all types of white blood cells with distinct functions. Basophils are involved in inflammatory responses and allergic reactions, eosinophils primarily combat parasites and are also important in allergic reactions, while lymphocytes are vital for the adaptive immune response, including T cells and B cells that specialize in recognizing pathogens and producing antibodies. Understanding the roles and classifications of these cells is key for recognizing how the immune system functions and how to respond to various health issues.