Me
explain spring tides and how the positions of the sun earth and moon cause them?

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 first caused people to consider that the continents were once one large landmass?

Which water sources contribute to a river system? check all that apply. groundwater lakes rivers streams watersheds