Describe two different ways that earth's layers are defined.

Does the threat of global warming require international cooperation? why or why not?

What factors led to europe's global dominance in economic and political factors? what impacts did that dominance have on other peoples and environments?

Which of these is a drawback of using natural gas? a. it is fairly safe for use in homes.b. it burns more cleanly than crude oil products.c. scientists have developed new ways of extracting it.d. during its extraction, groundwater can be contaminated.