Mexico city is an example of how humans alter their environment because it was

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 is it necessary to obey social norms? write briefly.

Which organelle is marked with an x?