What backs the u.s money supply, in other words what gives the U.S dollar its value?

I need to survey 100 people for my A.P Econ class, and must know gender and age along with the response

The government, gender-male, age- 31

The US was taken off the gold standard many years ago. The US dollar, like many other international currencies, is backed by the "full faith and credit" of the US Government. In other words, it's backed by the US economy and the public's faith that when they pay with a dollar they will receive a dollar's worth in return.

Male 74