Why does the author mention the United States in the fourth sentence?

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.

martin luther believed that selling indulgences was wrong and gave people a license to sin. the roman catholic church used the practice of indulgences to raise money for major building projects.

the northwest ordinance of 1787 guaranteed basic rights for settlers and banned slavery there.

d. because in realality people do wanna buy things and when an item is sold alot the makers make the price least   thats what my gut saya lol