The most important result of the second industrial revolution was

depleting natural resources.
creating business empires.
turning the united states into a world economic power.
creating problems for labor, such as long hours.

turning the United States into a world economic power.

The Second Industrial Revolution occurred following the American Civil War until World War I.

The Second Industrial Revolution created major American industries putting the US on the economic global map. Steel and oil industries became the leading suppliers to the world in addition to many factories producing a host of manufactured and food goods. The ability to quickly industrialize made the US a primary hub of goods when World War I broke out.

they could have a boston tea party.

it foreshadows the theme of the paragraph and hints the topic that will be discussed in the paragraph!