What is the process by which sand dunes move forward on their downwind side?

Scientist believe that earths core is around 6000°c where does this heat come from

Japan is a group of four islands off the coast of asia. what effect do you think has had on the lives of the japanese?

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.