We did CC for a number of years though my 9th grader is now in a Christian school. I did supplement science in Challenge. When we were in it, 7-8th grade (Chall A-B) didn’t cover enough science material and 9-11th (Chall 1-3) used Apologia…far too YEC focused for us. In middle school we added the Prentice Hall Science Explorer series. At the school my son now attends, they use Campbell Biology in 9th & 10th and take the AP exam at the end of 10th. That might be a good approach if you are in CC, because they do Physical Science in 9th which according to the publisher (Apologia) is a middle school text. Then they do Apologia Biology in 10th grade. If you did Bio in 9th and AP Bio in 10th (with Campbell or whatever texts you prefer…Miller-Levine is great for 9th grade), you’d get the review in class in Chall B at least. That’s what we were planning to do before we decided CC was not the best fit for us.
Even if you’re not in CC, Prentice Hall Science Explorers is a great curriculum for middle school level science. They have about 15 short textbooks that cover life science, earth science and physical science (chem + physics).
We haven’t used Novare but their books look intriguing. I believe they are in the process of writing the Bio text…they have all the other middle and high school sciences.