What is the surface of Spain?

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

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

Which of the layers of the earth has the following three characteristics? i. it is made of molten rock. ii. it has currents that are constantly moving. iii. earth’s plates float on top of its currents.