A particular high school has end-of-course exams in (E3) English 3, (E4) English 4, (M) Advanced Math, (C) Calculus, (W) World History, (U) U.S. History, (B) Biology, and (P) Physics. No English 3 students are taking English 4, World History, or Biology; no English 4 students are also in Calculus, Advanced Math, U.S. History, or Physics; no Physics students are also taking Advanced Math; No World History students are also taking U.S. History; and no Advanced Math students are also taking Calculus.

1. Create a graph in which the vertices represent the exams, and an edge between a pair of vertices indicates that there are no students taking both exams.

2. Find the complement of the graph in part 1.

3. Explain what the graph in part 2 represents.