Describe5 marksStandard
When a plant is short of water, abscisic acid (ABA) is produced and triggers a signalling pathway that results in stomatal closure. Describe the role of ABA and calcium ions in this process.
CAIE A Level Biology 9700 · Homeostasis
Homeostasis: describe 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.
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.
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