What weapons did plain people use out of buffalo bones?

Many were used as a hammer Carver and even a knife

All sorts! Different tools like saws, forks, hammers, knives and weapons in combat like making a sword or spiking the end of the bone like a spear or large knife.

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.