CAIE A Level Biology 9700 · Biological molecules
The blood plasma of mammals contains dissolved ions such as Na+ and Cl−, and glucose. Mammals also maintain a constant body temperature. Using your knowledge of the structure of water, explain how hydrogen bonding gives water properties that make it suitable for transporting dissolved substances and for helping mammals regulate body temperature.
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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