What occurred as a result of immigrants, free blacks, and other ethnic groups living together in the northern cities?

a. a new form of construction
b. cooperation among groups
c. crime and violence
d. greater interest in crafts

i think it is d korean

macon. i believe thats the answer

sorry if im wrong.

answer: the time zones used to be whatever the local authority wanted them to be. one town might have 6am whenever the sun came up and another town had 6am 10 minutes later.  

the trains had a hard time when their orders said to be at a certain point at 6am.  

6am, but who's 6am.  

the railroads got together and set the time zones more or less along the longitude lines across the country.

explanation:

i normally just use