Complex sentence: Repeated U.S. questions have yielded several different responses from the Russian government regarding Mount Yamantau, including it is a mining site, a repository for Russian treasures, a food storage area, and a bunker for leaders in case of nuclear war.
Split into simpler sentences: Repeated U.S. questions have yielded several different responses from the Russian government regarding Mount Yamantau. They have said it is a mining site, a repository for Russian treasures, a food storage area, and a bunker for leaders in case of nuclear war.