Final answer:
West Africa was most involved in the Trans-Atlantic slave trade; the Northeast was associated with the Mourning Wars; and the Pacific Northwest is known for the potlatch practice.
Step-by-step explanation:
The region most directly involved in the trans-Atlantic slave trade was West Africa. This region was crucial for the sourcing of enslaved people, who were then transported across the Atlantic Ocean to various parts of the Americas. In contrast, the Mourning Wars are historically associated with the Northeast region of what is now the United States, and the practice of potlatch is culturally significant in the Pacific Northwest region. These regional associations were pivotal in shaping the social and political dynamics of the respective areas.