What was needed as a surplus to create trade between cultures?

500 books can be produced by one man and a printing press within 5 months, while a copyist can only produce one in the same amount of time

d) a week

because the land run of 1889, although not without precedent in the history of the west, further, their men were aboard the first trains, ready to jump off and begin staking their claims. oklahoma city, edmond, and guthrie were all so affected.