PLS HELP ITS ABOUT PLANETS THSNKS

The earth's internal process which drives seafloor spreading is

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.

In what three areas is the us leader?