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

The gas exchange system — practice question

In the photomicrograph, a cross-section of a bronchus is shown. What function do tissues X and Y carry out?

  • AX: secrete mucus; Y: prevent collapse of the airway
  • BX: support the airway; Y: dilate airway
  • CX: trap dust and dirt; Y: secrete mucus
  • DX: waft dust and dirt upwards; Y: constrict airway

Worked solution & mark scheme

This 1-mark question has a full step-by-step worked solution and mark scheme.

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI