Page 331 Exercise 3

I asked my daugher when she was 8 to color each of the graphs below. 
I told her that she could use only two colors and that she couldn't put the same color on any circles connected by a line. After giving me a chagrined look, she told me that it couldn't be done with the first graph.  As is obvious this  graph contains an odd cycle.  To alternate colors,  you must exclude odd cycles because the first and last vertices will be of the same color.  Two coloring the second graph, which contains an even cycle, is
quite easy.