CAIE A Level Biology 9700 · Transport in mammals
Explain how the changes in pressure in the left atrium, left ventricle, and aorta during one complete cardiac cycle cause the opening and closing of the atrioventricular and semilunar valves. In your answer, refer to the sequence of pressure changes and the state of the valves at each stage.
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.
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