Define White Blood cells (WBCs)
WBCs are also called leukocytes, as they are colourless. They are the army of the human body. Whenever a germ or infection enters our body, the WBCs snap to attention and destroy the culprit. Their primary function is to produce antibodies (humoral immunity) or kill the invading bacteria directly (cytotoxic immunity). We will learn more about this later in the next unit on the Immune System.