_who help the office _ in the investigation

norsemen from northern countries had made earlier journeys

lee and grant, both of whom held the highest rank in their respective armies, had known each other slightly during the mexican-american war (1846-48) and began their dialogue by exchanging awkward personal inquiries. characteristically, grant had arrived in his mud-splattered field uniform while lee had turned out in full dress attire, complete with sash and sword.

explanation:

these civilizations were located around fertile rivers, where they could produce an abundance of crops