Which river makes up a large part of the boundary between mexico and the united states?
mississippi river
rio grande
amazon river
rio de la plata

According to the earth science reference tables, during which geologic time period were the continents of north america,south america, and africa closest together?

In the construction of new housing development, which factor of production can be categorized as land?

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.