Answer:
I hope this helps you
Explanation:
they were allowed to bring and trade enslaved people

A river valley civilization is an agricultural nation or civilization situated beside and drawing sustenance from a river. A "civilization" means a society with large permanent settlements featuring urban development, social satisfaction, specialization of labor, centralized organization, and written or other formal means of communication. A river gives the inhabitants a reliable source of water for drinking and agriculture. Additional benefits include fishing, fertile soil due to annual flooding, and ease of transportation. The first great civilizations, such as those in Mesopotamia and Ancient Egypt, all grew up in river valleys. Tigris River flourished near Mesopotamia civilization and river nile flourished near civilization of Egypt.
<h2>ꜰᴏʟʟᴏᴡ ᴍᴇ❤</h2>
Spain
the spanish civil war that happened in the 1930's after a failed coup is considered as a precursor to ww2 to because of the way it sucked foreign powers into it. the defeat of the republicans was caused by this interventon, which angered their foreign supporters.