How does one determine the exact elevation of a mountain on a topographic map?

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

Dry land planting can benefit the environment by reducing the need for tillagate

Ocean crust is a. made from submerged continents b. magnetically produced crust c. produced at mid-ocean ridge d. produced at all plate boundaries