Why are agricultural products hard to grow in northern alaska?

What does president obama say about modern day "hoovervilles"?

General rochambeau general washington by

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.