The following chunks of HTML code both produce the same thing in a browser...

This is just a simple example sentence.

Method 1:
<P><FONT FACE="Arial, Helvetica, sans-serif"><FONT SIZE="4"><FONT COLOR="teal">This is just a simple <FONT COLOR="red"><FONT SIZE="5">example</FONT></FONT> sentence.</FONT></FONT></FONT></P>

Method 2:
<P><FONT FACE="Arial, Helvetica, sans-serif" SIZE="4" COLOR="teal">This is just a simple <FONT COLOR="red" SIZE="5">example</FONT> sentence.</FONT></P>

The second one is much more efficient, taking up less storage space on the server and downloading faster.