What is the vocabulary word for new stone age?

Why is paper currency considered flat money ? a) it is backed up with gold and silver deposits b) it has value because people will accept it in exchange for a good or service c) it is easy to carry and transfer

This is the mountain range known as the alps. which of these statements regarding the alps is true? a) the alps are the largest mountain range in asia. b) the alps protect the roman empire from invasion. c) the alps were key in preventing england from being conquered in warfare. d) the alps prevented the roman empire from taking control of most of europe.

What are the most populous and least populous areas of russia? and why are some areas more heavily populated than others?