Final answer:
Passive immunity refers to the type of immunity where antibodies are acquired from an external source, rather than being produced by the patient's own immune system, either naturally or artificially such as through antivenom or serum.
Step-by-step explanation:
The immunity provided by antibodies that the patient did not manufacture themselves is called Passive immunity. Passive immunity can be acquired both naturally and artificially. An example of natural passive immunity is the transfer of antibodies from a pregnant person to their developing fetus. Alternatively, an example of artificially acquired passive immunity is the administration of antibodies through an antivenom or a serum to fight an infection.
Active immunity, on the other hand, involves the body's own immune response to an infection or immunization (vaccination). Vaccines are crucial in this context as they expose individuals to killed or weakened pathogens, without causing the disease, thus leading to the development of immunological memory and a protective immune response.