Which of the following accurately describes innate immunity?

• A. It is only present in vertebrates.
• B. It improves its response upon repeated exposure to the same pathogen.
• C. It provides a non-specific, immediate defense against pathogens.
• D. It generates highly specific antibodies after exposure to antigens.

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the concept of innate immunity. Innate immunity is the first line of defense in an organism's immune system and is present in both vertebrates and invertebrates. It is non-specific, meaning it does not target specific pathogens but provides a general defense against a wide range of invaders.
2. Step 2: Compare innate immunity to adaptive immunity. Adaptive immunity is specific and improves its response upon repeated exposure to the same pathogen, generating highly specific antibodies. Innate immunity, on the other hand, does not have this capability and does not improve with repeated exposure.
3. Step 3: Evaluate the options provided in the question. Eliminate any statements that describe characteristics of adaptive immunity, such as improving its response upon repeated exposure or generating highly specific antibodies.
4. Step 4: Focus on the statement that accurately describes innate immunity. It provides a non-specific, immediate defense against pathogens, which aligns with the definition and function of innate immunity.
5. Step 5: Confirm your understanding by recalling examples of innate immunity mechanisms, such as physical barriers (skin, mucous membranes), chemical barriers (enzymes in saliva, stomach acid), and cellular responses (phagocytes, natural killer cells). These mechanisms act quickly and non-specifically to protect the organism.