Which statement best differentiates innate and adaptive immunity?

• A. Innate is non-specific with no memory; adaptive is specific and develops memory
• B. Innate is specific with memory; adaptive is non-specific with no memory
• C. Both are non-specific with no memory
• D. Both develop memory but only adaptive is specific

Answer: (A)

This question tests how innate and adaptive immunity differ in specificity and memory. Innate immunity provides immediate, broad defense against pathogens and does not create lasting memory of encounters. It includes physical barriers, phagocytes, natural killer cells, and complement, and it responds the same way to repeated exposures. Adaptive immunity, on the other hand, is highly specific to particular antigens and builds immunological memory through B and T lymphocytes. This memory leads to a faster and stronger response upon subsequent exposures to the same pathogen.

The best statement captures these differences: innate is non-specific with no memory, while adaptive is specific and develops memory. The other statements either swap the characteristics or claim both arms are non-specific or lack memory, which does not align with how these two branches operate.