<p>I want to buy the Earth Science review pack from barronsregents.com (not the physical books, but the test/question back from the site because it comes with explanations). It costs $25 for six months. I just want to know if it is worth it. My main question for Earth Science is: how many topics can you test by? What are the different topics you can select the Regents by? I already know you can test by date, but I want to know how many topics you can test by. Thanks!</p>