<span>The answer is D. Immigration is the universal development of individuals into a goal nation of which they are not locals or where they don't have citizenship so as to settle or live there, particularly as perpetual inhabitants or naturalized natives, or to take-up work as a transient specialist or briefly as a remote.</span>
He was the vice president to FDR and the letter I suppose you're asking for is the one he wrote in 1952 titled "Why I was wrong"
The choices can be found elsewhere and as follows:
A. being conquered by the Mayans.
B. Francisco Pizzaro's trap that helped capture and kill the Incan emperor and his men.
C. that the Spanish had superior weapons.
D. that the Spanish brought with them
I think the correct answer is option A. All of the following aided in the decline of Incan Empire except being conquered by the Mayans. Hope this answers the question.
The Nile river and the fertile land along its banks
