Which statement about the impact of the twentieth-century technology is correct?

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

Match the mountains with the type of collision that formed them. a. andes b. aleutians c. north american cordillera d. appalachians 1. continental- continental 2. continental- oceanic 3. oceanic- oceanic 4. arc- continent

In plate tectonics, why is the north american plate tectonically inactive?