CAIE A Level Biology 9700 · Homeostasis
A person becomes dehydrated after prolonged exercise without drinking water. Describe the sequence of events that occur in the body in response to a decrease in blood water potential, including the roles of the hypothalamus, posterior pituitary, ADH, aquaporins, and the collecting ducts.
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.
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