Point-based marking
Most 6-mark IGCSE Biology questions use point-based marking: the mark scheme lists 7–8 possible marking points, and any 6 of them earn full marks. This means you have some flexibility in which points you include, but you must make at least 6 distinct, valid scientific statements.
What examiners scan for
Examiners read through your answer looking for each marking point in turn. They tick (✓) each valid point. They are trained to award marks even if the point appears in a different order from the mark scheme, or is phrased differently, as long as the scientific content is present.
This means the content matters more than the writing style. Clear, separate points are easier to mark (and therefore more likely to be credited) than a dense paragraph where points are buried.
How to structure your answer
- Write one distinct point per sentence: do not combine multiple ideas into one long sentence
- Use numbered points or new lines for each idea: this makes marking points visible
- Aim for 7–8 points to give yourself a buffer (some may not be on the mark scheme)
- Use precise scientific terminology: "enzyme active site changes shape" not "enzyme stops working"
- Include a logical sequence: cause → mechanism → effect
Common 6-mark topics
These topics frequently appear as 6-mark questions: explain how the small intestine is adapted for absorption, explain how the heart pumps blood through the double circulatory system, explain how blood glucose is regulated by insulin and glucagon, explain the process of natural selection, explain how factors affect the rate of transpiration.