What is imperialism, and how could the competition to create an empire potentially cause a war?

Imperialism is a policy, or a goal, which has as its aim extending one's influence over other countries.

It can lead to a war if the other country, the one that the empire wants to gain control over, resists, or if another empire is interested in it and fights with this empire over this new country.

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.