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

Mount erebus, an active volcano, is located a. in australia's snowy mountains b. on new zealand's north island c. in antarctica d. on melanesia's largest island

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.

What factors influenced brazil's current and future economic strength?