Given below are two statements. One is labelled Assertion (A) and the other is labelled Reason (R).

Assertion (A) : Polymorphonuclear leucocytes are cellular barriers. 

Reason (R) : Macrophages destroy microbes by phagocytosis.

In light of the above statements, choose the correct answer from the options given below.

Both (A) and (R) are true but (R) is not the correct explanation of (A).

Assertion (A) is true. Polymorphonuclear leukocytes, also known as neutrophils, are cellular barriers involved in the innate immune response. They play a critical role in defending the body against microbial pathogens by engulfing and destroying them through a process called phagocytosis.

Reason (R) is also true. Macrophages are immune cells that destroy microbes by phagocytosis. They engulf and digest pathogens, debris, and foreign substances, contributing to the body's defense against infections and maintaining tissue homeostasis.

While both Assertion (A) and Reason (R) are true and related to the immune response, Reason (R) does not directly explain why polymorphonuclear leukocytes are considered cellular barriers. Polymorphonuclear leucocytes act as barriers by actively migrating to sites of infection and engulfing pathogens, whereas macrophages function similarly but are not specifically referred to as cellular barriers.