Because it was a living thing.
Federalism is one of the central principles of American Constitutionalism because helps in the dividing and sharing of power between state and national governments, thus, making organization of the government manageable and standardized.
The other major principles of American Constitutionalism are:
Popular Sovereignty; Checks and Balances; Limited Power of the Government; Separation of Branches.
I guess there should be options to choose. Anyway, I know that the answer is: Christopher Columbus planned to find a more direct route to Asia by <span>sailing west across the Atlantic Ocean</span>. He convinced Spanish government to finance a plan to find a rout to Asia through the west across Atlantic. He reached the Caribbean but he thought that he reached West Indies island. This is how European colonization of America began.
Human activities that contribute to desertification include the expansion and intensive use of agricultural lands, poor irrigation practices, deforestation, and overgrazing. These unsustainable land uses place enormous pressure on the land by altering its soil chemistry and hydrology.
