Select all of the answers that apply.

Which statements are true regarding the scientific evidence supporting the big bang theory?

Researchers found cosmic microwave background radiation, which is a heat imprint left over from the big bang.
Quasars have been observed exploding and expanding from a single, hot, dense singularity.
A primordial form of helium gas was found by the Endeavor space shuttle.
A redshift of light emitted by stars and galaxies indicates the universe is expanding.
Redshift and blueshift of light emitted by stars and galaxies indicate that universe is expanding and contracting.