CAIE A Level Biology 9700 · Transport in mammals
The mammalian heart is adapted for double circulation. Explain how the structure of the heart, including the thickness of its walls and the coordination of its beat, ensures efficient blood flow through the pulmonary and systemic circuits.
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.