Explain5 marksStandard
Explain how the structure of alveoli and their associated capillaries are adapted to maximise the rate of gas exchange between alveolar air and blood.
CAIE A Level Biology 9700 · Gas exchange
Gas exchange: explain question
How this question is marked
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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