A college course may have one or more scheduled sections, or may not have a scheduled section. Attributes of COURSE include Course ID, Course Name, and Units. Attributes of SECTION include Section-Number and Semester-ID. Semester-ID is composed of two parts: Semester, and Year. Section-Number is an integer (such as "1" or "2") that distinguishes one section from another for the same course but does not uniquely identify a section. How did you model SECTION? Why did you chose this way versus alternative ways to model SECTION?