1 .		In simple terms, how does the Earth rate as a planet? Compare its size, density, composition, and other basic properties with those of its neighbors. How would you expect study of other planets to help us understand our own?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
2 .		Distinguish between evolutionary processes and cyclic processes. What are examples of each that we have encountered so far in this book? Why are cyclic processes more common on the Earth than on the Moon?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
3 .		Make sure you understand how plate tectonics work. Can you describe how this process gives rise to mountains, volcanoes, deep-sea trenches, and earthquakes? What does plate tectonics tell us about the fate of deep-sea sediments, including the carbonates that trap most of the carbon dioxide that would otherwise be in our atmosphere?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
4 .		The changes in geological thinking that resulted from the acceptance of plate tectonics and continental drift constituted one of the major scientific revolutions of the twentieth century. Why do you think these ideas were so slow in being widely adopted? You may wish to compare this scientific revolution with others of the past century: Darwin's discovery of the role of natural selection in biological evolution; Pasteur's proof of the role of germs in causing disease; the insights into human psychology provided by Freud; and the revolution in physics represented by relativity, quantum mechanics, and the discovery of the nature of the atom.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
5 .		Compare the ocean crust and the continental crust, in terms of composition, origin, and evolution. Are these two divisions of the terrestrial crust at all analogous to the division of the lunar crust into highlands and maria? Explain.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
6 .		Discuss the chemical balance that exists between the land, the ocean, and the atmosphere. Imagine what would happen to the other two if any one of these were dramatically changed.   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.