An ecumenopolis is a theoretical construction in which the entire area of Earth that is taken by human settlements, or at least, that those are linked so that to create an urban areas so big that they can shape an urban continuum through thousands of kilometers.
Agriculture has been greatly effected since the beginning of the 20th century. Partly due to WW1 and WW2 thus increasing the product demand and cause price spikes.
Trade was a commonly used way to obtain items back in the day, people would give one item in exchange for another, allowing people to have access to items they didn't have before.
The American Revolution was principally caused by colonial opposition to British attempts to impose greater control over the colonies and to make them repay the crown for its defense of them during the French and Indian War (1754–63)