Which is a cause of voluntary migration?

Name the two rivers that run through the fertile crescent. how were the rivers both positive and negative to societies of the fertile crescent?

The earth rotates on its axis and revolves around the sun every

Ascientist 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?