They realized that nothing really changed much. The freed African-Americans still had almost no political rights and the system was controlled mostly by corrupt politicians who came from the north to become rich. The regular people still had huge farms and turned the former slave system into a system of sharecropping which was in many ways similar to slavery. The freedom was very superficial and in reality people still lived as bad as before the war.
We don't have enough information to answer this question, but i believe what you're trying to find is that the Muslim armies carried their faith west across the top of the entire continent.
Hopes this helps, if it doesn't please add information onto your question, like example, the choices you were given.
Have a Good Day
The north launched an offensive against the south that lead to the overwhelming of the south and the fall of Saigon.
