What are the two main sections of the human immune system?

What are the two main sections of the human immune system?

• A. Innate and Adaptive
• B. Humoral and Cellular
• C. Primary and Secondary
• D. Passive and Active

Answer: (A)

Two main sections of the immune system are innate and adaptive. The innate part acts quickly and non-specifically, using physical barriers like skin and mucous membranes, phagocytes such as neutrophils and macrophages, natural killer cells, the complement system, and inflammation to blunt many invaders at once. The adaptive part develops a targeted response over time, recognizing specific antigens and providing tailored attacks through B cells (humoral immunity, antibodies) and T cells (cellular immunity), with memory that speeds future responses. The other terms describe aspects within the adaptive response or different concepts entirely, not the primary division of the immune system.

Two main sections of the immune system are innate and adaptive. The innate part acts quickly and non-specifically, using physical barriers like skin and mucous membranes, phagocytes such as neutrophils and macrophages, natural killer cells, the complement system, and inflammation to blunt many invaders at once. The adaptive part develops a targeted response over time, recognizing specific antigens and providing tailored attacks through B cells (humoral immunity, antibodies) and T cells (cellular immunity), with memory that speeds future responses. The other terms describe aspects within the adaptive response or different concepts entirely, not the primary division of the immune system.