I would guess that this is very high school dependent. At our kids’ HS, AP Chem and AP Bio do not require taking a prior Chem or Bio class, and it’s actually not possible to do so within the curriculum. Students take
- basic physics in 9th grade
- either Chem or AP Chem in 10th grade
- either Bio or AP Bio in 11th grade
- option to take AP Physics or another science elective in 12th grade