What is the U.S. dollar backed by?

Could you elaborate on the fundamental backing of the U.S. dollar? As the world's reserve currency, it holds significant influence in global finance, yet I'm curious about its intrinsic value. Does it rely primarily on the trust and credibility of the U.S. government? Or is there a tangible asset, such as gold or another commodity, that underpins its value? How has the dollar's status evolved over time, and what factors have contributed to its continued dominance in the global economy? Understanding the fundamental basis of the U.S. dollar's value is crucial in navigating the complex world of cryptocurrency and finance.