Describe three pieces of evidence that support the big bang theory.

Answer:

Three pieces of evidence that support the big bang theory are: 1) The redshift of distant galaxies, which shows that the universe is expanding. 2) The cosmic microwave background radiation (CMBR), which is the leftover heat/radiation from the initial explosion. 3) The abundance of light elements, specifically hydrogen and helium, which match the predicted composition of the early universe.