7. which of the following rivers is the world's busiest waterway? a. rhone b. rhine c. danube d. seine

The impact of a large asteroid comet with earth has been proposed to have caused the extinction of the dinosaurs. the impact site of this comet is in or near

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.

This diagram show the most important texts of.