One significant difference between oceanic and continental crust in terms of the long term evolution of the earth's surface is that

The difference(s) between the grand canyon and valles marineris is/are: (a) the grand canyon was formed by water, but valles marineris was not. (a) valles marineris is much longer than the grand canyon. (c) valles marineris is much wider than the grand canyon. (d) valles marineris has large volcanoes near it. all of the above

What causes the cyclical changes in the appearance of the moon?

Most countries in the middle east must import a majority of their a. gasoline b. oil c. food d. water