What prehistoric species emerges to battle for the great plains?

Bison and Mammoths

Explanation:

There is evidence that mammoths where present in the plains

so they can defeat there oppenent

- three-quarters or two-thirds..

- "the constitution provides that an amendment may be proposed either by the congress with a two-thirds majority vote in both the house of representatives and the senate or by a constitutional convention called for by two-thirds of the state legislatures."

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