Root elements are usually defined as complex type as they can contain numerous data types and objects within them
. Within root elements, there is a 'sequence' of child objects. The available data types for these are; "element", "simpleType", "complexType", "date", "integer", to name just a few. Within XML Schema Documents, you may often see elements with a prefix 'xs:', or 'xsd:', this is a standard to define schema tags.