Match List-I with List-II: List-I Types of barriers List-II Examples…

The correct answer is Option (4) → (A)-(II), (B)-(III), (C)-(IV), (D)-(I)

(A) Physical barriers — this matches (II) Skin. The skin is the main barrier that stops the entry of micro-organisms. Mucus lining the respiratory, digestive and urogenital tracts also traps microbes.

(B) Cellular barriers — this matches (III) PMNL-neutrophils. Polymorpho-nuclear leukocytes (neutrophils), monocytes and natural killer cells, and macrophages in tissues, engulf and destroy microbes.

(C) Physiological barriers — this matches (IV) Acid in the stomach. Stomach acid, saliva and tears stop microbes from growing.

(D) Cytokine barriers — this matches (I) Interferons. Virus-infected cells release interferons, which protect the non-infected cells from further viral infection.

NCERT Extract:
Innate Immunity – “… Innate immunity consist of four types of barriers. These are — (i) Physical barriers : Skin on our body is the main barrier which prevents entry of the micro-organisms. … (ii) Physiological barriers : Acid in the stomach, saliva in the mouth, tears from eyes–all prevent microbial growth. (iii) Cellular barriers : Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes. (iv) Cytokine barriers : Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection.”