I think the correct answer is
(A) changing in abiotic factors
Answer:
While these mounds take many forms and served different purposes, with each in a sense telling its own story, all were built entirely by hand, usually by piling up earth one basket-full at a time. Some served as burial mounds for the honored dead, while other flat-topped mounds were parts of large cities or towns and held temples or ceremonial buildings, and still others were built in the shape of giant animals.
Because the British kept on taking away more of there rights and they were doing taxation without representation which basically means that they were taxing the colonist without the colonist having a representative over in Britain to speak for them.
