What this practice covers
These questions are drawn from past CIE 9700 Biology papers and filtered to the gas exchange system. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
Start practising practice questions →
What examiners see students get wrong here
These are the errors that cost marks on the gas exchange system, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying bronchioles contain cartilage. They do not, and this is the single most tested fact in the topic.
- Saying alveoli have goblet cells or cilia. They have neither, because both would be too thick.
- Saying the alveolar wall is "thin" without saying it is one cell thick.
- Saying a large surface area alone explains fast exchange. The short distance and the maintained gradient matter just as much.
- Saying ventilation maintains the gradient, and stopping there. The blood supply is the other half.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: The gas exchange system revision notes.