The three correct answers that provide evidence of universe expansion supporting the Big Bang Theory are:
- An enormous amount of weak cosmic background radiation has been detected in the universe.
- Galaxies are moving away from each other.
- The temperature of the universe is decreasing.
These points relate to the observed cosmic microwave background radiation, Hubble's Law indicating redshifted galaxies moving away from us, and the overall cooling of the universe since the Big Bang.