Question

select the correct answer. when an antigen attacks the body, it activates adaptive immunity. this adaptive immunity produces a strong response when it encounters the same antigen for the second time. which feature of adaptive immunity is essential for this kind of response? a. the ability to remember the antigen it encounters b. the ability to distinguish between self and nonself antigens c. the ability to produce nonspecific antibodies against the foreign antigen d. the ability to secrete lysozymes against pathogenic antigens

Explanation:

To solve this, we analyze each option:

• Option A: Adaptive immunity has immunological memory. When an antigen is first encountered, the immune system "remembers" it. On re - exposure, this memory allows a stronger and faster response. This matches the situation described (stronger response on second encounter).
• Option B: Distinguishing self and non - self is important for the immune system to not attack the body's own cells, but it is not related to the stronger response on re - encountering the same antigen.
• Option C: Adaptive immunity produces specific antibodies, not nonspecific ones. Nonspecific immunity is part of the innate immune system.
• Option D: Lysozyme secretion is part of the innate immune system (e.g., in tears, saliva), not adaptive immunity.

Answer:

A. the ability to remember the antigen it encounters