Humans have acquired immune system that produces antibodies to neutralize pathogens. Still innate immune system is present at the time of birth because it
Answer: (C) has natural killer cells which can phagocytose and destroy microbes.. Answer: (C) has natural killer cells which can phagocytose and destroy microbes.
- A.is very specific and uses different macrophages.
- B.produces memory cells for mounting fast secondary response.
- C.has natural killer cells which can phagocytose and destroy microbes.✓
- D.provides passive immunity.
Correct Answer
(C) has natural killer cells which can phagocytose and destroy microbes.
Solution & Explanation
Answer: (C) has natural killer cells which can phagocytose and destroy microbes. Solution: Innate immunity is the non-specific defence present at birth. Its cellular barrier includes natural killer cells (a type of lymphocyte) along with neutrophils and macrophages that can phagocytose and destroy microbes, giving immediate protection before acquired immunity develops. Why others are wrong: Innate immunity is non-specific (not 'very specific'), it has no memory cells for a secondary response, and memory/passive responses belong to acquired immunity. NCERT Reference: NCERT Ch7, p.134-135, lines (p134) 33-56, (p135) 3-5: "natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes"