Explain why your project needed XML.
Remember XML was meant to exchange data between the two entities as you can define your user friendly tags with ease. In the real world scenarios the XML is meant to exchange data. For illustrate you have two applications who want to exchange information. But as they work in two complete opposite technologies it is difficult to do it technically. For illustrate one application is made in JAVA and the other in .NET. But both the languages understand XML so one of the applications will spit XML file which will be consumed and parsed by other applications. You can give a scenario of two applications which are working individually and how you chose XML as the data transport medium.