Can somebody please answer my last 3 questions? i'll give u brainliest

According to the article, what did plato and aristotle have in common?

Were african-americans allowed to serve in the military in wwi? explain

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.