One of the main reasons john d. rockefeller was able to succeed in the oil industry was because he
a) encouraged competition.
b) treated his competitors fairly.
c) combined vertical and horizontal integration.
d) urged government regulation of the oil industry.

In shifting to a defense policy based upon the concept of "flexible response," president kennedy was indicating that he had grave doubts about thevalue of which previous defense policy? a massive retaliationb collective securityc containmentd air power

Interest groups representing businesses and investors are often among the most successful lobbying groups for all of the following reasons, except a. such groups have the financial resources to mount sustained campaigns on their own behalf b. these groups' members contribute heavily to many legislators' campaigns and in so doing gain greater access to legislators c. these groups have often been in existence for decades, allowing them to both master the legislative system and develop close ties with legislators d. the members of these groups make up the majority of voters in many districts

In what is known as the great migration, large numbers of african americans moved from the rural south to northern cities, beginning in the early twentieth century. what motivated this large-scale movement?