Please help me, I don't understand Which is true about the “push-pull” theory of voluntary migration?

The transatlantic slave trade pushed millions of Africans against their will to the European colonies.

People migrate because their personal difficulties “push” them to leave.

In the 1840s, a disease destroyed the potato crop in England, pulling people to migrate.

People migrate because a lack of religious freedom “pulls” them to a new country.

20 points the two basic principles of economics are (choose two) question 2 options: a. the wants of society and individuals are limited. b. the wants of society and individuals are unlimited. c. the resources of society are limited. d. the resources of society are unlimited.

Does increased security engender feelings of increased safety or does it increase the fears that people have?

It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. in fact, however, simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills—suffices. evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills. which of the following, if true, most seriously weakens the force of the evidence cited? (a) as people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them. (b) many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation. (c) many people are proficient both in social interactions and in solving mathematical problems. (d) the study did not itself collect data but analyzed data bearing on the issue from prior studies. (e) the tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.