Innate immunity is ______.

• A. only found in vertebrates
• B. a non-specific defense mechanism present from birth
• C. a highly specific response developed after exposure to pathogens
• D. mediated exclusively by antibodies

Answer: (B)

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 from birth.
2. Step 2: Recognize that innate immunity is non-specific, meaning it does not target specific pathogens but rather provides a general defense against a wide range of invaders.
3. Step 3: Compare innate immunity to adaptive immunity. Adaptive immunity is highly specific and develops after exposure to pathogens, whereas innate immunity is immediate and does not require prior exposure.
4. Step 4: Note that innate immunity is not mediated exclusively by antibodies. Instead, it involves physical barriers (like skin), chemical barriers (like stomach acid), and cellular responses (like phagocytes).
5. Step 5: Eliminate incorrect options based on the characteristics of innate immunity and identify the correct description: 'a non-specific defense mechanism present from birth.'