CAIE A Level Biology 9700 · Transport in plants
In a herbaceous dicotyledonous plant, the xylem and phloem are responsible for long-distance transport. Describe the structure of xylem vessel elements and phloem sieve tube elements (including companion cells). In your description, explain how each structural feature is related to the cell's function in transport.
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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