Where were the mayans discovered first?

I think they were discovered in guatamala but idk for sure 

In Central America which is nowadays Yucatan, Campeche, Tabasco, Quinta Roo... all that area.

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.