Scientists find that a plant chemical reduces bacterial growth. At a low dose it does not damage human cells, but at a high dose it does.
Which conclusion is supported by these findings?
the chemical may be useful, but the dose will need to be controlled
the chemical will be harmless, because it is produced by a plant
the chemical will be useless, because a high dose damages cells
the chemical may be useful, so increasing the dose will improve safety
45 exam-style questions on Edexcel GCSE Biology 5.2 Plant and body defences, covering 5.2.1 Physical plant defences, 5.2.2 Chemical plant defences, 5.2.3 Detecting plant diseases, and 5.2.4 Human physical and chemical defences. Each one has a worked solution and a mark scheme showing where the marks go.