PLEASE HELP I DON'T KNOW

The most common economic system in the world is aclosed economy. command economy. mixed market economy. traditional economy.

Nuclear experimentation is a major global issue that affects relationships between countries. describe why countries try to limit the testing of nuclear weapons.

Which of the following best describes brazil's economy from 1650-1880? a. it gradually shifted to manufacturing as the industrial revolution progressed. b. it was based on mining. c. it was based on plantation agriculture, where slaves served as a labor force. d. it was based on small, family-owned farms.