FIRST PERSON TO ANSWER WILL BE GIVEN BRAINLIEST

A scientist is explaining how background cosmic radiation gives evidence of the big bang theory. She says that radiation has been detected everywhere equally as heat in the universe and is increasing. This has been shown to be residual radiation from the big bang.

What error did the scientist make?

The radiation is not from the big bang, but caused it.
Radiation is not detected everywhere equally.
The amount of radiation should be lessening, not increasing.
This is not related to the big bang theory.