CAIE A Level Biology 9700 · Transport in mammals
The aorta is the largest artery in the body. Its wall contains a high proportion of elastic fibres. During the cardiac cycle, the aorta expands when the left ventricle contracts and recoils when the ventricle relaxes. Explain how this elastic recoil helps to maintain continuous blood flow and influences the formation of tissue fluid in the capillaries.
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.