What is a good analogy for democracy?

Toward the end of the roman empire, what caused a decrease in the use of coined money tell me now

In the kingdom of saudi arabia the government controls every aspect of oil production which makes up the majority of the country's economy. while other businesses are owned by individuals, the biggest segment of saudi arabia's economy is oil production. saudi arabia's economy would best be described as a) entirely market. b) almost entirely command. c) a mixture between just market and traditional. d) a mixed economy with large amounts of command.

The physical feature that makes up part of the border between canada and the united states is the