How do customs preserve the distinctive identity of a community? ​

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.

Restricting immigrants from entering a country may be based on what belief?  

Recently, there has been pressure to loosen clean air standards. use economic arguments to support or oppose this proposed action.