1. Run BFS on the graph from node 20, highlighting the edges in BFS tree. For each vertex, write the distance from the source in a table. When there are multiple choices for the next node, iterate over nodes in ascending order of their number.

2. Run DFS on the graph starting from node 20, highlighting the edges in the DFS tree. For each vertex, write the corresponding discovery and finishing times. When there are multiple choices for the next node, iterate over nodes in ascending order of their number.

3. Run the cut-vertex algorithm based on your DFS tree in the previous question. Calculate all the low numbers and then determine which nodes are the cut-vertices and why.