Question: What is the name of a National Preserve located in the Flint Hills region of Kansas and is home to a population of genetically pure American bison?
Sentence (from "Big Cypress National Preserve"): The 720000 acre Big Cypress, along with Big Thicket National Preserve in Texas, became the first national preserves in the United States National Park System when they were established on October 11, 1974.
Relevant evidence: No