Answer: B. Infighting among its member tribes
C. Attacks by English colonists
Step-by-step explanation:
Iroquois League was simply referred to as a collection of tribes that their main aim was promotion of peace. The longhiuse which was building in the shape of a rectangle was invented by the Iroquois.
The Infighting that occured among the member of its tribes coupled with the attacks by English colonist led to the
weakening of the Iroquois confederacy in the eighteenth century.