Passive artificial immunity is provided by:

Passive artificial immunity is provided by:

• A. Infection
• B. Vaccination
• C. Injection of immune serum
• D. Maternal antibodies

Answer: (C)

This question focuses on how passive immunity can be provided, specifically that passive artificial immunity is achieved by giving someone pre-formed antibodies rather than eliciting their own immune response. Injecting immune serum introduces antibodies from another person or animal directly into the recipient, providing immediate protection. This is temporary because the host’s immune system isn’t activated to produce its own antibodies, and the externally supplied antibodies are eventually cleared. In contrast, infection leads to active immunity acquired naturally, as the body mounts a response and develops memory. Vaccination provides active artificial immunity by stimulating the body's own immune response to produce antibodies and memory. Maternal antibodies are a form of passive immunity, but they are natural, not artificial.

This question focuses on how passive immunity can be provided, specifically that passive artificial immunity is achieved by giving someone pre-formed antibodies rather than eliciting their own immune response. Injecting immune serum introduces antibodies from another person or animal directly into the recipient, providing immediate protection. This is temporary because the host’s immune system isn’t activated to produce its own antibodies, and the externally supplied antibodies are eventually cleared.

In contrast, infection leads to active immunity acquired naturally, as the body mounts a response and develops memory. Vaccination provides active artificial immunity by stimulating the body's own immune response to produce antibodies and memory. Maternal antibodies are a form of passive immunity, but they are natural, not artificial.