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

The gas exchange system — practice question

Which flow diagram correctly shows the effect when tar enters the lungs?

  • Acarcinogens come into contact with DNA → mutation occurs → uncontrolled cell division → mass of cells produced
  • Bgoblet cells secrete more mucus → mucus accumulates causing infection → phagocytes attracted by inflammation → causes irritation and coughing
  • Cgoblet cells secrete more mucus → mutation occurs → phagocytes attracted by inflammation → mass of cells produced
  • Dphagocytes attracted by inflammation → mutation occurs → uncontrolled cell division → elastase destroys the alveolar walls

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