R-13.8 Explain why the DFS traversal runs in (n2) time on an n-vertex simple graph that is represented with the adjacency matrix structure. C-13.6 Show that if a graph G has at least three vertices, then it has a separation edge only if it has a separation vertex. C-13.10 Show that, if T is a BFS tree produced for a connected graph G, then, for each vertex v at level i, the path of T between s and v has i edges, and any other path of G between s and v has at least i edges