CAIE A Level Biology 9700 · Transport in plants
A student is examining a photomicrograph of a transverse section of a herbaceous dicot stem. They identify xylem vessel elements and phloem sieve tube elements. Describe the structural features of xylem vessel elements and phloem sieve tube elements that are adapted to their functions, and explain how each feature relates to its function. You may present your answer in continuous prose or as a table.
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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