Name 3 human made features that are shown on a topographic map

What is a reasonable action that provides safe water for communities?

If the distance between two points on the ground is 10 miles and the distance between the same two points on a map is 4 inches, what is the map scale expressed as a ratio?

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?