Java - Some aspect of each of the following can be modeled with a graph structure. Describe, in each case, what nodes would represent and what the edges would represent.

1. Trips available using a specific airline
2. Countries and their borders
3. A collection of research articles about data structures
4. Actors (research the six degrees of Kevin Bacon)
5. The computers at a university
6. A labyrinth
7. The web