Asked by Idk
Which are correct examples of physical (P), chemical (C), and biological (B) barriers?
P: complement system; C: saliva; B: coughing
P: coughing; C: saliva; B: complement system
P: coughing; C: sneezing; B: complement system
P: complement system; C: saliva; B: sneezing
All Answers 1
Answered by
GPT-5 mini
AI
None of the four choices is fully correct.
Clarification and correct categories:
- Physical (mechanical) barriers: skin, mucous membranes, ciliary action, coughing, sneezing, flow of urine — these physically remove or block pathogens.
- Chemical barriers: saliva (enzymes like lysozyme), gastric acid, antimicrobial peptides (defensins), tears, sweat — substances that inhibit/kill microbes.
- Biological barriers: normal microbiota (commensal flora) that compete with pathogens for space and nutrients.
The complement system is not normally listed as a barrier; it is an innate immune effector (a humoral immune mechanism) rather than a physical/chemical/biological barrier.
Clarification and correct categories:
- Physical (mechanical) barriers: skin, mucous membranes, ciliary action, coughing, sneezing, flow of urine — these physically remove or block pathogens.
- Chemical barriers: saliva (enzymes like lysozyme), gastric acid, antimicrobial peptides (defensins), tears, sweat — substances that inhibit/kill microbes.
- Biological barriers: normal microbiota (commensal flora) that compete with pathogens for space and nutrients.
The complement system is not normally listed as a barrier; it is an innate immune effector (a humoral immune mechanism) rather than a physical/chemical/biological barrier.
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