Water that flows downhill along the earths surface

Using complete sentences, explain the differences between a command economy and a market economy. what type of economic system is created when these two systems are combined? what are the benefits of combining these two systems?

What evidence does the writer give to support his argument about coral reefs? a) he speaks of the activities of coral polyps. b) he describes the composition of the great barrier reef. c) he emphasizes the ways in which coral reefs are fragile. d) he points out the ways that scientists do research on the reefs.

Which of the following types of nonrenewable fuel sources requires the storage of radioactive waste? a. coal b. nuclear c. solar d. oil