Biology 9700 · AS & A Level · The gas exchange system

The gas exchange system — practice question

What observation would suggest a difference in the structure of the gas exchange system of a cigarette smoker and a non-smoker?

  • Aabsence of ciliated epithelium
  • Bdecrease in elastic fibres
  • Cenlargement of goblet cells
  • Dincrease in smooth muscle

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