Augustin de iturbide was able to declare independence from spain while also proclaiming himself emperor in part because

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.

it proved indian land claims were unjustified.

i would say it is the roman empire europe after the norman conquest.