A researcher heats three leaf samples in ethanol and then adds iodine solution. The results are shown in the table.
| Leaf sample | Appearance after heating in ethanol | Colour after adding iodine solution |
|---|---|---|
| A | green | dark green |
| B | pale | orange-brown |
| C | pale | blue-black |
The researcher concludes that samples A and C contained starch, but sample B did not.
Evaluate the researcher's conclusion.
117 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.