How is hydrofracking used to obtain natural gas from rocks deep in the earth?

How much water is in the ocean in cubic kilometers

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 type of seismic waves are confined at the surface