What five factors combined to end the open-range cattle industry?

One factor was barbed wire. As farmers and ranchers wisened up, they used the wire to fence in their cattle, destroying the use of cowboys, and taking away one aspect of the "wide open west".  Herds of cattle took over the plains and destroyed the grass. In 1883 the big drought struck and water streams dried up and prairie fires grazed. Also the barbed wire and the natural disasters.

2. a land bridge connected asia and north america thousands of years ago.

4. crossing the land bridge would have been simple for the first migrants.

5. people might have crossed a land bridge while hunting animals.

a memoir is the correct answer