When a country develops, what happens to the quality of life and standard of living for the people who live there?

What does the word submerged mean in the following sentence? after it rained for three days in a row, the streets were completely submerged.

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

Crisis in rivalries between the serbs, croatians and muslims has been going on for centuries and only intensified during the 1990s when non-communist rulers were elected