Answer:
- CMB radiation and a very early form of helium were discovered
- Redshift of distant stars and galaxies indicate the universe continues to expand.
Step-by-step 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).