Active immunity develops when the body responds to an antigen. Which option matches this definition?

Active immunity develops when the body responds to an antigen. Which option matches this definition?

• A. The body does not respond to pathogens
• B. Antibodies are transferred from another individual
• C. The body produces antibodies after exposure to an antigen
• D. It is only inherited genetically

Answer: (C)

Active immunity happens when the immune system encounters an antigen and mounts its own response, producing antibodies and memory cells. This involves B cells becoming plasma cells that secrete antibodies and T cells coordinating the attack, with memory cells ready to respond faster next time. Exposure can be natural (infection) or artificial (vaccination), and the key feature is that the body is actively producing its own antibodies rather than relying on someone else’s antibodies. That direct production of antibodies after encountering an antigen best matches the concept. In contrast, not responding to pathogens shows no immunity, transferring antibodies from another person describes passive immunity, and being inherited describes a genetic or innate type of protection rather than an active, self-generated response.

Active immunity happens when the immune system encounters an antigen and mounts its own response, producing antibodies and memory cells. This involves B cells becoming plasma cells that secrete antibodies and T cells coordinating the attack, with memory cells ready to respond faster next time. Exposure can be natural (infection) or artificial (vaccination), and the key feature is that the body is actively producing its own antibodies rather than relying on someone else’s antibodies. That direct production of antibodies after encountering an antigen best matches the concept. In contrast, not responding to pathogens shows no immunity, transferring antibodies from another person describes passive immunity, and being inherited describes a genetic or innate type of protection rather than an active, self-generated response.