XHTML structure

Had a question the other day, by a friend of mine who is learning basic HTML, on WHAT each of the parts of an XHTML page mean, and where they come through in a browser.

I did these two diagrams - yes very simple, but in plain language, to explain how HTML works.

The first diagram is the WHOLE XHTML document, and what each of the bits mean.
The second diagram is how the browser interprets the code.

If you are an educator, feel free to use it. Just acknowledge where you got these diagrams from.

And if you see any errors, or can think of anything to add on, let me know! ;)