What city is located at the branching point between the white and blue nile

Why might have people followed the rivers to find their way into asia

Why does less erosion & more deposition take place on the outside bank of a meander?

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