What industry was John D Rockefeller a giant in?

What are the difference between fair trade and normal trade? What is the development of normative system within school? Which term refers to groups of farmers who pool their money to make large purchases of tools seed and other supplies at a discount? Is the gold standard still in use? Did people in the 1950's earn good money? What does a marginal capacity to work mean? Who made gold expensive? What part of speech is the word monopoly? How many people work in the tertiary sector in the UK? The time between when the fed adjust the money supply and when interest rates change reflects the what lag? Why were cash economies introduced by the European unsuitable for African countries? How much money does a Wisconsin dairy cow produce? What is the Economy Act? What are the main differences in level of development between countries? Because the goods offered for sale in a competitive market are largely the same? Characteristics of managerial Managerial economics? What is will earn in it's future progressive tense form? Goods are scarce because people desire much more than the economy can produce.How can this scenario worsen the economic situation of the nation? What is 50000 dollars in 1980 is worth how much today? What is the equivalent value today of a shilling in 1891?

What industry was John D Rockefeller a giant in?