What countries border greece on the north?

The countries that border Greece to the north are Macedonia, Albania, Bulgaria, and also Turkey. These countries throughout history have been part of different empires and political configurations but in modern times these are the countries bordering Greece. 

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.