According to the ruling in dred scott, congress was prohibited
a. admitting new states to the union
b. granting citizenship to african americans
c. prohibiting slavery in the territories

the correct answer is prohibiting slavery in the territories.

i believe that the answer to the question provided above is that  establishing smaller ethnic communities within larger communities  gives more chance for people to know each other more but this might lead to the  conflict between groups.

its whatever your mind tells you