What were three factors that help lead the aggressive expansion westward?

1. Gold rush and mining opportunities (silver in Nevada)
2. The opportunity to work in the cattle industry; to be a “cowboy”
3. Faster travel to the West by railroad; availability of supplies due to the railroad.
4. The opportunity to own land cheaply under the Homestead Act.

He made the polygraph too,but thomas edison was not falsely credited for the light buld