Answer:
b. British colonies' need for population.
b. Printers could produce copies of Greek and Latin texts and scientific research more rapidly.
Step-by-step explanation:
A "pull" factor is a benefit that is found in the country a person migrates to. In this case, that would be America. One of the benefits of America was the fact that the colonies needed population. This meant that land, food, housing and other needs were easily available when compared to Europe.
One of the benefits of the Gutenberg press was the fact that printers could easily produce copies of Greek and Latin texts. This allowed classic ideas to be rediscovered and admired, encouraging the Renaissance.