What section of a research paper should contain the main idea?

What affected the second industrial revolution have on transportation

Why was lee unable to escape from appomattox? he didnt not have the needed supplies grant had him surrounded davis had ordered him to surrender he was waiting for johnston to bring reinforcements

How does nafta affect relations between the united states and canada? a. it bans immigration between the two countries. b. it opens the borders between the two countries. c. it raises taxes on trade between the two countries. d. it allows free trade between the two countries.