McDougal Littell’s Class Zone site is on many of my Social Studies related “The Best…” lists — their interactives are incredible (the links I have in this post may, or may not, bring you directly to the interactives. If you get sent to a map, just click the subject you’re interested in and click on California. That will lead you to different textbooks — then click on one of them. That will lead you to the interactives).
However, I realize I’ve never written about their equally as impressive high school biology sites. It, too, has plenty of interactive, and most provide audio support for the text.
I’m sure it’ll be on my Best Sciences Sites of 2011 list at the end of the year.