What is the difference between active immunity and inactive immunity?

Active immunity occurs when the immune system is exposed to a pathogen and produces its own antibodies in response, often following vaccination or natural infection. This type of immunity is long-lasting, as memory cells are created to recognize the pathogen in future encounters. In contrast, passive immunity involves the transfer of antibodies from another source, such as through maternal antibodies in breast milk or antibody treatments; it provides immediate but temporary protection since the recipient's immune system does not produce its own antibodies.