Which of the following statements about acquired immunity is accurate?

• A. It develops after exposure to specific antigens.
• B. It does not involve memory cells.
• C. It is present at birth and provides immediate protection.
• D. It is solely mediated by physical barriers such as skin.

Answer: (A)

Verified step by step guidance

1. Understand the definition of acquired immunity: it is the immunity that develops after exposure to specific pathogens or antigens, unlike innate immunity which is present at birth.
2. Recall that acquired immunity involves the activation of lymphocytes (B cells and T cells) and the formation of memory cells, which allow for a faster and stronger response upon subsequent exposures to the same antigen.
3. Evaluate each statement: the one stating 'It develops after exposure to specific antigens' aligns with the concept of acquired immunity because it is adaptive and specific.
4. Recognize that the statement 'It does not involve memory cells' is incorrect because memory cells are a hallmark of acquired immunity.
5. Note that 'It is present at birth and provides immediate protection' describes innate immunity, and 'It is solely mediated by physical barriers such as skin' also refers to innate immunity, not acquired immunity.