What are the chemical weapons involved with the first line of defense?
a. oil and sweat glands within skin
b. mucus and cilia lining the respiratory tract
c. saliva and digestive enzymes
d. all of these are correct

d. all of these are correct

Explanation:

Physical barriers are the first line of defense against invading agents. Examples of physical barriers include intact epithelia, the normal microbiota residing in these epithelia, and normal mucosal self-cleaning processes such as coughing, sneezing, mucus production, gastric acidity, vomiting, diarrhea, and urinary flow. All of these processes together make up a very efficient line of defense.

We can mention some members of the body's first line of defense, they are:

Skin: It is the main barrier that the body has against pathogens. Skin Oil and Sweat Glandulas: It has fatty acids that help the skin to prevent fungus from entering the skin. Mucus: It is a fluid produced by the body that has the function of preventing microorganisms from entering the respiratory system, for example. Saliva: It has a substance that maintains the lubrication of the mouth and helps protect against viruses that can invade the organs of the respiratory and digestive system. Digestive Enzymes: They act on the digestion of food and prevent the proliferation of microorganisms. Cilia lining the respiratory tract: Protect the respiratory tract against the entry of microorganisms and invasive substances.

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