Which of the following rivers is the world's busiest waterway

In the diagram below dab and dac are adjacent angles

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?

Horizon a is also sometimes called a. topsoil b. subsoil c. bedrock d. weathered bedrock