Match List I with List II : List I List II A Natural infection by a microbe I Passive immunity B Injection of preformed antibodies II Physiological barrier C Rejection of a transplanted organ III Active immunity D Acid in the stomach IV Cell-mediated immunity Choose the correct answer from the options given below :

Step-by-step solution

Natural infection by a microbe leads to the production of antibodies in the host body, which is known as active immunity. Thus, A matches with III. Injection of preformed antibodies provides immediate protection and is known as passive immunity. Thus, B matches with I. Rejection of a transplanted organ is primarily caused by the cell-mediated immune response, which involves T-lymphocytes. Thus, C matches with IV. Acid in the stomach acts as a physiological barrier of innate immunity by preventing microbial growth.