Question

after being exposed to the flu, a patient starts making anti - flu virus antibodies. this is an example of __________ immunity.
a artificial active
b artificial passive
c natural active
d natural passive

Explanation:

To determine the type of immunity, we analyze each option:

• Artificial active immunity is acquired through vaccines (artificial exposure), so A is incorrect.
• Artificial passive immunity involves receiving pre - formed antibodies (e.g., immunoglobulin therapy), so B is incorrect.
• Natural active immunity occurs when a person is naturally exposed to a pathogen (like the flu virus here) and their immune system responds by producing antibodies. This matches the scenario.
• Natural passive immunity involves receiving antibodies from an external source (e.g., from mother to child), so D is incorrect.

Answer:

C. natural active