Difficulty between lower and upper level courses

[Mian]

Is there any correlation between difficulty between lower and upper level courses? I know it is necessary to take foundation courses in science and math because the next layer builds on that. I do see courses that are upper level that don't seem to have introductory courses. Does college follow the high school paradigm of each grade being progressively more difficult?

I don't think so. I've taken some lower level classes that were really difficult and some upper level classes that weren't. It really depends on the subject, your learning style and the school/instructor.