CAIE A Level Biology 9700 · Gas exchange
A person has a genetic condition that results in non-functional cilia on the ciliated epithelial cells lining the trachea. Describe how ciliated epithelial cells and goblet cells normally work together to protect the gas exchange system from pathogens and particulate matter.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.