Which is best to use in order to find the straight distance between two far distant points on the earth?

What was the first official pair of sister cities?

Which of the following statements best explains why there tends to be a greater number of large cities in southern africa than the east africa

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?