Which best describes a development that improved railroad safety?

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 of these was an accomplishment of the han dynasty? the invention of the seismograph finding a water passage to europe the invention of the ballpoint pen the invention of the abacus

Choose the major southeast asian civilizations covered in this chapter. malaysia dai viet monsoon angkor champa