Differentiate innate immunity from adaptive immunity.

• A. Innate is immediate and non-specific; Adaptive is slower, specific, and generates memory
• B. Innate is memory-based; Adaptive is non-specific
• C. Innate is slower and highly specific; Adaptive is immediate
• D. Adaptive immunity does not involve lymphocytes

Answer: (A)

Timing, specificity, and memory distinguish the two arms of the immune system. Innate immunity provides an immediate, non-specific defense using barriers (skin, mucous membranes) and general cellular responses like phagocytes and natural killer cells. Adaptive immunity is slower at first because it must recognize specific antigens and then activate B and T lymphocytes to mount a targeted response, including antibody production and cytotoxic actions. A key feature of adaptive immunity is immunological memory—memory B and T cells that respond quickly and more effectively if the same pathogen reappears.

So the correct idea emphasizes that innate is fast and non-specific, while adaptive is slower, highly specific, and capable of memory. The statements that innate is memory-based or that adaptive is non-specific aren’t accurate, and adaptive immunity clearly involves lymphocytes as primary mediators.