1) What is XML?
The Extensible Markup Language (XML) is a general-purpose specification for creating custom markup languages.[1] It is classified as an extensible language, because it allows the user to define the mark-up elements. XML’s purpose is to aid information systems in sharing structured data.

2) What is the version information in XML?
The root element can be preceded by an optional XML declaration element stating what XML version is in use (normally 1.0); it might also contain character encoding and external dependencies information.

3) What is ROOT element in XML?
XML documents must contain one element that is the parent of all other elements. This element is called the root element.