The Louisiana Purchase proved to be one of the shrewdest business pacts in the entire history of our country. First, it doubled the area of the United States and provided territory from which fourteen new states were created either wholly or in part. Second, it gave us full control over the mouth of the Mississippi River and opened up the way to foreign trade. Prior to the Purchase, the waterway had been blocked by the Spanish fleet, probably with the approval of Napoleon. Third, the land was rich in timber, minerals, and natural resources of other kinds. And finally, the cost of the transaction was incredibly low. The total of $15,000,000 amounted to approximately four cents an acre.

Q. Write three words which prove that the author organized his facts by order of importance.