Which is a sentence?

Are being studied to learn more about human impact.

The exotic species that live there.

Examining the water and pollution levels.

Rain forests and swamps are fragile ecosystems.

Read the paragraph. theodore roosevelt was the greatest president because as a leader of the progressive party, he brought about much-needed social, political, and economic reform. one of his economic reforms was to break up many large business trusts. by doing so, he took economic power out of the hands of the wealthy and powerful corporations and placed it in the hands of the ordinary people. theodore roosevelt’s reform policies, known as the square deal, to give the average citizen an equal share of opportunities. which sentence is the thesis of this paragraph? theodore roosevelt was the greatest president because as a leader of the progressive party, he brought about much-needed social, political, and economic reforms. one of his economic reforms was to break up many large business trusts. by doing so, he took economic power out of the hands of the people and placed it in the hands of the ordinary people. theodore roosevelt’s reform policies, known as the square deal, to give the average citizen an equal share of opportunities.