Answer :
British and French disputes over the borders in the Ohio River Valley was one of the major causes of the opening of the American front in during the Seven Years War. This conflict would later come to be known as the French and Indian War.
Answer;
Britain and France disputed borders in the Ohio River Valley.
Explanation;
-The cause of French and Indian War was the fact that the French and the English wanted to claim the land where the Allegheny, Ohio, and Monongahela Rivers meet (present-day Pittsburgh), a costly war broke out.
-Both the French and the English believed their explorers were the first to claim this land where the three rivers meet.
-Additionally, both countries wanted to keep the fur trade with the Native Americans.