Describe three common problems that have often been faced by command economies. what kinds of issues have encouraged many countries to switch to mixed or market systems?

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.