Skin and mucous membranes are mostly involved in:

• A. Adaptive immunity.
• B. Autoimmunity.
• C. Irregular immunity.
• D. Innate immunity.

Answer: (D)

Verified step by step guidance

1. Understand the concept of innate immunity: Innate immunity is the body's first line of defense against pathogens. It is non-specific and provides immediate protection through physical barriers, chemical barriers, and immune cells.
2. Identify the role of skin and mucous membranes: Skin and mucous membranes act as physical barriers that prevent the entry of pathogens into the body. They are part of the innate immune system.
3. Differentiate between innate and adaptive immunity: Innate immunity is immediate and non-specific, while adaptive immunity is specific and develops over time with exposure to specific antigens.
4. Consider the characteristics of autoimmunity and irregular immunity: Autoimmunity involves the immune system attacking the body's own cells, while irregular immunity is not a standard term in immunology.
5. Conclude that skin and mucous membranes are involved in innate immunity due to their role as physical barriers and their immediate, non-specific action against pathogens.