How were African americans made aware of oppurtunities in northern and western industries? a]by people like Harriet Tubman
b] from advertisment in black newspaper
c] on television news channel
d]by the owners of the land that they worked on

This link explains it

The correct answer is a. when they started making tools that will them in cultivating lands, they could raise crops and that made them attached to one place for a longer period of time. after that, they started domesticating animals and building their own permanent settlements that resemble the ones we have today.