$[10$ marks$]$ Run breadth first search on this network, and draw the resulting breadth first search tree being careful to label the tree vertices with their corresponding letters in the graph. You should start at vertex $a,$ and explore vertices in alphabetical order when the algorithm gives you a choice.

Making reference to the tree, justify whether or not the graph is bipartite.

$[10$ marks$]$ Find all articulation points of the graph shown below by depth first search from vertex $r.$ Examine edges with lower numbers first.