Prerequisites allow you to restrict access to a course until all its prerequisite courses have been passed. In this way, you can create learning paths for your learners.
However, circular references for prerequisites are not checked, so it is your responsibility to ensure there are no circular references. So for example, if we have two courses, “Cooking 101″ and “Advanced Cooking”, we must check to make sure both courses don’t have each other as a prerequisite, otherwise a learner would never be able to take the course.