Computer science

Computer science a paper on XML, does not need to be very fancy I just need to answer these questions: 1 What is XML? 2 Why XML? 3 Features of XML 4 Difference between XML and HTML 5 Rules for writing a XML Document. 6 What is a well formed XML Document? 7 What is a valid XML Documents 8 What are the two types of XML definitions? 9 What are the meaning of all symbols such as *? +, |, ATTLIST, REQUIRED, IMPLIED, etc. 10 What is XPath? 11 How to draw a tree structure? Write a XPATH expression. 12 How to write a simple XML documents based on the tree structure.