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

The gas exchange system — practice question

What might be observed in a photomicrograph of the trachea wall?

  • Aelastic fibres: present; epidermis: present; smooth muscle: present
  • Belastic fibres: present; epidermis: present; smooth muscle: absent
  • Celastic fibres: present; epidermis: absent; smooth muscle: present
  • Delastic fibres: absent; epidermis: present; smooth muscle: absent

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