All of the following protect the skin and mucous membranes from infection except

The question is incomplete. Th ecomplete question is as following:

All of the following protect the skin and mucous membranes from infection EXCEPT  

A) multiple layers of cells.

B) tears.

C) saliva.

D) HCl.

E) the "ciliary escalator."

D) HCl.

Explanation:

Whereas HCL helps in the digestion process.

Hence, the correct option is D.

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.

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