PreRequisites and Waitlists
Sometimes you are required to complete a course or class before you can be considered eligible to enroll in another class. These pre-enrollment requirements are referred to as prerequisites. Once these prerequisites have been completed, the learner may then enroll in the next class.
Other times, a class turns out to be overwhelmingly popular. When there are more students signing up than there are available seats in the class, that is when a waitlist comes into play. A waitlist is essentially an online queue for people signing up for a class. If one person in the class happens to drop the course, the first person in the queue is automatically added to the roster.