Review for Module X10d: Coding XHTML

   1. Discuss the evolution of XHTML from HTML and XML
   2. Explain why XHTML is preferable to HTML
   3. Discuss the policy of separating format from structure
   4. Describe the XHTML Doctype tag
   5. Describe the XHTML Namespace declaration
   6. List the tags that can remain open in HTML but must be closed in XHTML
   7. List the HTML tags that are to be avoided in XHTML, and the 
      alternatives to using them;
   8. Discuss the need to use lowercase in all tags.