A(n) is an economic barrier because it limits trade between two nations, while a(n) is an economic barrier because it completely blocks trade between two nations. a) quota, embargo b) embargo, tariff c) blockade, quota d) blockade, tariff

The telegraph, the transatlantic telegraph cable, and the telephone were important to businesses after 1850 because of a. they created a system for developing new inventions. b. they filled a need that other inventions of the day could not. c. they attracted investors and created the stock market. d. they made picture-taking a popular american pastime.