biological investigtions often require the support of referenced material, not only in the form of text or data, but also as diagrams or drawings. Care must be taken to supply references for illustrations taken sources. Students must avoid the temptation to supply illustions for their own sake. Illustrative material should only be included if it enhances the argument or supplies information that cannot be easily provided in another way. Original photopraphs,photocopies or downloaded images that are not labelled or put into the context of the investigation are unlikeky to enhance the essay.