Question

Which one of the following is a physical barrier ?

• A. Mucus coating on the epithelium lining the urogenital tract
• B. Acid in the stomach
• C. Tear
• D. Saliva

Answer 1

Answer:

A. Mucus coating on the epithelium lining the urogenital tract

• The mucus coating acts as a physical barrier, trapping pathogens and preventing them from reaching the epithelial cells and causing infection.

• This is a classic example of a physical barrier in the immune system.