The evidence provided in the above excerpt most directly reflects which of the following changes to the lives of north american indians?

Hello!

This excerpt?

“The tough sod discouraged farming, and the plains animals were too fleet of foot to provide a dependable supply of food for large numbers of pedestrians. Then the horse gave the Indian the speed and stamina needed to take advantage of the opportunity to harvest this immense quantity of food represented by the buffalo herds of North America and the herds of wild cattle that propagated so rapidly in the grasslands of both Americas. The Indians stopped farming; the work was hard, boring, and unrewarding, compared to the nomadic life.”

Taken from: Alfred W. Crosby, Jr., historian, The Columbian Exchange: Biological  and Cultural Consequences of 1492, published 1972  

The buffalo (its meat) would become a vital and the most important resource for the American Indian people in the plains.

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"a government in which power is divided between state and national levels". federalism is a system of government in which entities such and state and province, share power with the national government.