Disadvantages and advantages of using a river as a boundary

Maria is going to a hiking trip this weekend. she has been busy shopping for the trip. which of these items that she bought are a want for her?

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?

Is an official language in every north african country