Solution 4.2.7.1.

Here are two spanning trees.

A graph with seven vertices arranged in three rows: two on top, three in the middle, and two on bottom. The vertex on the middle left is adjacent to the vertex on the top left. This is adjacent to the vertex in the middle of the middle row, and the vertex on the top right. The top right vertex is adjacent to the middle right, which is adjacent to the vertex on the bottom right, which is adjacent to the vertex on the bottom left. Thus there are a total of 6 edges.
A graph with seven vertices arranged in three rows: two on top, three in the middle, and two on bottom. The vertex in the middle of the middle row is adjacent to the four vertices on the top and bottom rows. The vertices on the top row are each adjacent to the vertices in the middle row on their side. Thus there are a total of 6 edges.
in-context