1.2 In a tool such as Gradescope that manages multiple courses, a course enrolls multiple students but may initially have no students enrolled. A student may be enrolled in multiple courses but doesn't have to be enrolled in any course that uses Gradescope. However, a student will only be enrolled in a particular class once. Each course must have at least one assignment, but may have many. However, each assignment is associated with exactly one course at all times. Students can submit solutions for assignments. If they do, they can only submit once, but they may not submit anything for a particular assignment.