What minerals can be cut and polished giving them a beautiful appearance are 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.

Name the three types of population distribution

While viewing a topographic map, you notice a region in which the contour lines are very close together. what can you conclude about this region? a. it has a high population. b. it has a steep incline. c. it's near a political boundary. d. it contains a body of water.