What are the two main types of immunity in the human body?

The two main types of immunity in the human body are innate and acquired. Innate immunity, also known as nonspecific immunity, is the body's first line of defense and is present from birth. It includes physical barriers like skin and mucous membranes, as well as various immune cells that respond immediately to pathogens. Acquired immunity, also referred to as adaptive immunity, develops over time as the body is exposed to specific pathogens. This type of immunity involves the activation of lymphocytes, such as T cells and B cells, which create a targeted response and provide long-lasting protection against future infections from the same pathogens.

Understanding these two types is crucial because they work together to protect the body from infections. Innate immunity is fast and immediately acts against a wide range of pathogens, while acquired immunity takes longer to activate but provides a more effective and specific response, leading to immunological memory.

The other options offer different classifications or aspects of immunity but do not represent the primary division. For example, natural and artificial immunity typically refer to how immunity is obtained rather than the fundamental categories, while active and passive immunity describe the mechanisms of response and transfer of antibodies rather than the types of immunity itself. Cellular and humoral immunity, on the other hand, refer to specific