The ciriculation of water from earth's surface to the atmosphere and back is called

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 is a measure of the amount of light a star directly emits? a. luminosity b. wavelength c. brightness d. intensity

Which of the following regions suffers the most from acid rain? a. the area around vancouver c. the area below atlanta b. the area below detroit d. the area above montreal