What does "cyclone" mean?​

Acontinental polar air mass foms in

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.

Scientists believe that differences in cause hot, plastic-like rock in the asthenosphere to rise toward earth's surface. a. density c. weight b. magnetism d. composition c. conduction. d. density.