There are a few ways to determine whether a course requires a prerequisite. One way is to look over your degree completion worksheet (DCW). In your DCW, prerequisites for a course are listed in parenthesis next to the course.
Another option available currently is to review the course description section of the current Catalog.
Additionally, when you go to register in Populi, if you click on the course you would like to take, the prerequisites will be listed in the course description.