Question

Assertion: Natural immunity or innate immunity comes into play immediately or within hours of antigen’s appearance in the body.
Reason: By mechanisms such as physical barriers like- skin, chemicals in the blood and immune cells that attack the foreign antigen in the body.

• A. Both assertion and reason are false
• B. Both assertion and reason are true and reason is the correct explanation of the assertion
• C. Both assertion and reason are true but the reason is not the correct explanation of the assertion
• D. Assertion is true but the reason is false

Answer 1

The correct option is B Both assertion and reason are true and reason is the correct explanation of the assertion

Innate immunity occurs naturally due to genetic factors, and is not induced by any prior infection or vaccination. It is the first line of defence that attacks the foreign invaders/antigen immediately after their appearance in the body, which is neither specific nor adaptive and is constantly available to reduce the workload of the adaptive immune response.

As a first line of defence there are different substances that obstruct the entry of the pathogens into the body like physical, chemical etc. Physical barriers like skin and mucous membranes function as the continuous impassable barrier to potentially infectious pathogens.

Chemical barriers like low pH, antimicrobial molecules etc., make the survival of the pathogens hostile and eliminate the cellular pathogens and also immune cells like phagocytes attack the foreign antigen in the body finally leading to elimination of the invading pathogen.