How did volcanoes affect the origins of the seas?

In 2002, north korea announced that it was shutting down its nuclear facilities constructing a hydroelectric energy plant restarting nuclear weapon development changing to a free market economy

The desert expands by hundreds of square miles each year.

The caste system in india was used for what purpose? a) to ensure that all people had an adequate income b) to prevent the rich from taking too much power c) to provide social control and conformity according to one’s birth d) to draft a military capable of defending india from mongol invasion