The document discusses key concepts about the World Wide Web and XHTML including:
- The World Wide Web is a subset of the Internet that allows sharing of web pages written in XHTML.
- Web browsers like Internet Explorer and Firefox are used to view web pages by requesting them from web servers.
- XHTML is the markup language used to structure and present content on web pages. It is based on HTML.
- Common XHTML tags are used to structure content like the <html>, <head>, <title>, <body>, <p>, <b>, <i> tags.
- Additional elements like images, headings, hyperlinks, and lists can be added to web pages using tags like <img