The federal entity created by the Constitution is by far the dominant feature of the American governmental system. (1)_____ the system itself is in reality a mosaic, (2)_____ of thousands of smaller units—building blocks which together (3)_____ the whole. There are 50 state governments (4)_____ the government of the District of Columbia, and further down the ladder are still smaller units, (5)_____ counties, cities, towns and villages. This (6)_____ of governmental units is best understood (7)_____ the evolution of the United States. The federal system, it has been seen, was the last step in the (8)_____ process. Prior to its creation, there were the governments of the (9)_____ colonies (later states) and prior to (10)_____, the governments of counties and smaller units. One of the first tasks (11)_____ by the early English settlers was the creation of governmental units for the tiny (12)_____ they established along the Atlantic coast. Even before the Pilgrims disembarked (13)_____ their ship in 1620, they (14)_____ the Mayflower Compact, the first written American constitution. And as the new nation pushed (15)_____ each frontier outpost created its own government to manage its affairs. The drafters of the U.S. Constitution left this multilayered governmental system (16)_____. While they made the national structure supreme, they wisely (17)_____ the need for a series of governments more directly in (18)_____ with the people and more keenly attuned(合拍) to their needs. Thus, certain (19)_____ such as defense, currency regulation and foreign relations—could only be managed by a strong centralized government. But (20)_____ such as sanitation, education and local transportation—belong mainly to local jurisdictions(管辖权).