Why was a direct military conflict avoided in Cuba?

Which of the following is an example of the pull factor known as economic migration? a. better educational opportunities pulling people towards a new country b. mexican laborers entering the us to work in agricultural jobs c. joining family members that are already in a new country d. crop failures driving people away from their country i am unsure on this question, i was thinking b? but i could be wrong.

Which situation would be considered an example of the freedom of association? a. three students write a letter to a local newspaper demanding that a teacher be fired. b. a group forms on a college campus to support a particular political candidate. c. an individual purchases a membership to a local gym. d. a religious organization buys several local lots in order to construct a new church building.

What notable contributions to science has sandia national labs (snl) produced over the years?