-skin, an impermeable barrier made of keratin
-cilia and mucus in lungs
-stomach acid (denatures/breaksdown pathogen)
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A-level Biology Notes
General FictionTopics 1-4 of A-level Biology AQA New specification
what are barriers?
-skin, an impermeable barrier made of keratin
-cilia and mucus in lungs
-stomach acid (denatures/breaksdown pathogen)