Exercise 9.

For each of the following, try to give two different unlabeled graphs with the given properties, or explain why doing so is impossible.

1. Two different trees with the same number of vertices and the same number of edges. A tree is a connected graph with no cycles.

2. Two different graphs with 8 vertices all of degree 2.

3. Two different graphs with 5 vertices all of degree 4.

4. Two different graphs with 5 vertices all of degree 3.