Question

Assertion (A) : pH of the body fluids prevent the growth of many organisms.
Reason(R) : It is a type of physical barrier which prevents the entry of microorganisms.

• A. Both assertion and reason are correct and reason is the correct explanation of the assertion
  
• B. Both assertion and reason are incorrect
• C. Both assertion and reason are correct but reason is not the correct explanation of assertion
  
• D. The assertion is correct but the reason is wrong
  

Answer 1

The correct option is D The assertion is correct but the reason is wrong


Innate immunity is the general protective mechanism of the body against any type of foreign invasions. It is there from birth. Physical and physiological barriers are part of innate immunity. Most of the microorganisms have a particular pH requirement for their growth and metabolic activities. The pH of our body fluids prevents the growth of microorganisms. It is a physiological barrier. For example, Acidity of sweat is pH 5.5 and acidity of stomach is pH 2-3, both kill the microorganisms.

Physical barriers include skin, mucus membranes etc. which prevent the entry of the microorganisms physically. Hence assertion is a true statement and reason is a wrong statement.