Which one help someone

Which of the following was a key accomplishment of the people of songhai? a. they had a strong military and became the largest empire in west africa. b. they established a center of islamic scholarship. c. they worked with iron and prospered from the gold-salt trade. d. they dominated in the trade of ivory, enslaved people, and animal skins.

Why learning about people and places around is important?

Which of the following items would serve as a primary source for a historian studiying the american civil war