A few mold spores land on the skin but do not survive due to the lack of moisture and the presence of oxygen. These spores have been prevented from harming the body by which type of barrier?

The skin’s dryness and the presence of oxygen create conditions that prevent some mold spores from surviving. This is a chemical barrier, which protects the body through chemical conditions or substances that inhibit pathogens. Therefore, the correct choice is biological.

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