Barron's Biology: CD-ROM?

<p>Hello,
I have a question about the Barron's SAT Subject Biology book. Is the version with the CD-ROM actually worth the extra money? What is on the CD? Is Barron's the best for me to get for the subject test? I've already done one year of IB Biology so the information is not new but needs to be refreshed and will be this year in school and through the book I choose.</p>

<p>Thank you!</p>