Denim jeans and barbed wire were both invented in 1873. Which of these would be placed first as the most important contribution to life on the frontier? Barbed wire would be placed first because it allowed more people to farm and have cattle.

Denim jeans would be placed first because Americans today use denim more than barbed wire.

Denim jeans would be placed first because their durability allowed farmers and ranchers to cut their clothing costs.

Barbed wire would be placed first because its use ended free grazing and helped close the frontier.