"which continents currently have sufficient water to meet the needs of their populations? "

Explain why components that are naturally found in air can be considered air pollutants.

Summary of the impact of the physical environment on settlement patterns and economic activities for ukraine

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.