3. Most people in Mexico and Central America choose to emigrate in order to
move somewhere warmer.
trade their goods.
find better jobs.
escape religious persecution

The right choice is:

Find better jobs.

Explanation:

Millions of Mexicans and Central Americans decide to go to the United States for two reasons mainly. The first reason is to look  for economic opportunities they don´t  have at home; they want  jobs that are better paid  and to escape poverty.

The second reason is equally important. Many people flee their countries because their personal safety is threatened by criminals gangs known as "maras" , from the threats of drug traffickers; for them, to stay home may mean death. This is particularly true in Guatemala, Honduras and El Salvador, though many Nicaraguans now flee their country to escape repression by the dictatorship of Daniel Ortega, an old leftist comandante who opposed the USA in the 1980s , but he came back to power in 2007.

i really really really really really really dont know

treating native americans justly and giving them equal rights as citizens of the united states" was not a way in which americans sought to solve the indian problem. removal was the most popular idea.