Describe5 marksStandard
Describe the sequence of events that leads to the closure of stomata in a plant experiencing water stress. In your answer, include the roles of abscisic acid (ABA) and calcium ions.
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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