How did eli whitney’s interchangeable parts improve production methods ?

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.

Why did reagan have the united stars invade grenada

To encourage railroad companies to build railroads across the west, the government gave them subsidies by select the best answer from the choices provided. a. paying the wages of laborers b. giving them building materials c. providing railroad trains d. providing free land