Real high schools have level systems to separate students by academic ability, if not AP or honors courses to further separate our future leaders from the future opioid addicts and pyramid scheme victims. Movies and television are always sorting characters into jock, nerd, and slacker roles -- which would absolutely have different schedules -- and then throwing them all into the same class and hoping nobody notices.
Teen shows will have the smartest kids in school taking the exact same class as the pothead four grades behind and the lineman about to get kicked off the football team for failing lunch. For instance, in Boy Meets World, Topanga winds up being the valedictorian, yet she's in class with Cory, the idiot, and Shawn, the wisecracking slacker. Even toward the end of high school, they have the exact same classes. Is this a Philadelphia school with only one classroom's worth of students?
On Saved By The Bell, Jessie is an obsessive overachiever who resorts to speed pills to study longer, Kelly is an airhead cheerleader, Screech is more like a chimpanzee than a human, and Zack is a sociopath who would break up an administrator's marriage in order to get out of class. And yet there they are, all in the same room.