CAIE A Level Biology 9700 · Homeostasis
After consuming a meal rich in protein, the body absorbs amino acids. Any excess amino acids cannot be stored. Explain why the liver converts the amino groups from these excess amino acids into urea and how this process contributes to homeostasis in mammals.
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.
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.
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