CAIE A Level Biology 9700 · Transport in plants
A student examines a transverse section of a stem from a herbaceous dicotyledonous plant. The xylem vessel elements are observed under a microscope. Explain how the structure of these xylem vessel elements is adapted for the efficient transport of water.
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.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.