Question

the primary barrier to protect the body against disease is:
a unbroken skin
b short fingernails
c protective gloves
d hand washing

Explanation:

The skin is the body's largest organ and acts as a physical barrier. Unbroken skin prevents pathogens from entering the body. Short fingernails (B) mainly prevent dirt accumulation but are not a primary barrier. Protective gloves (C) are external aids, not a natural primary barrier. Hand washing (D) reduces pathogens but is a hygiene practice, not the primary natural barrier.

Answer:

A. Unbroken skin