Natural immunity refers to the innate defenses that organisms possess to protect against infections without prior exposure to pathogens. This form of immunity includes physical barriers such as skin, as well as cellular components like phagocytes and natural killer cells. Unlike acquired immunity, which develops through exposure to specific pathogens and involves antibodies, natural immunity provides immediate, generalized protection against a wide range of infectious agents. It plays an essential role in the body's first line of defense, enabling quick responses to pathogens. Factors such as genetics and overall health can influence the effectiveness of natural immunity.