Answer:
The correct answer is E. All of the above
Step-by-step explanation:
The body contains different physical and chemical barriers to protect itself from the invasion of any pathogen. These barriers act as the first line of defense to the body and include skin, mucous membrane, acids, and antimicrobial enzymes.
Skin acts as a mechanical barrier to microbes and does not allow any pathogen to invade through it until it gets punctured.
Saliva contains antimicrobial enzymes like lysozyme which kills bacteria by destroying their cell wall. Hydrochloric acid released in the stomach is highly efficient to kill pathogens coming with food.
Mucous membranes in the digestive and respiratory tract contain WBCs, antimicrobial enzymes and proteins which kills the invaded pathogen like Vibrio.