Why did many african americans participate in the great migration?

Need on these last 2 questions on my social studies homework 5 and 6 then i’m done with the homework

In a command economy, people are not free toa buy consumer goods.b work in factories.c make production or monetary choices.d receive an education.

    which of the following was anecological  result of european exploration from 1400 to 1800?   a.  increased trade with east asia      b.  the spread of epidemic diseases      c.  expansion of english territory      d.  the spread of christianity