Which statements are true regarding scientific evidence supporting the big bang theory?
cmb radiation and a very early form of helium were discovered.
the universe has structure and uniformity.
redshift of distant stars and galaxies indicate the universe continues to expand.
sound waves of an explosion are heard light years away.

Explanation:

After the big bang, the remnants of the explosion are perceived mainly in the microwave spectrum ( after photon decoupling phase) that continues to fade as it diffuses across the expanding universe. As the universe expands, it causes the wavelengths of the photons to increase (relative to the observer who will view the galaxies moving away from him in red-shift).

"it built up in the atmosphere"

i think thats it, idk, i tried looking for this exact q& a for grad. and idk if i got this question right or sorry if im wrong