Which supreme court decision declared that federal restriction of slavery was unconstitutional? brown v. board of educationmissouri v. the united statesroe v. wadedred scott v. sandford?

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.