Which region has the greatest concentration of currently active volcanoes?

What factors did the founders of your state use to determine the states boundaries ? did you states founders choose boundaries based on physical features or lines longitude and latitude ?

In wegener’s evidence for continental drift, continents were proposed to fit together, such as the east coast of south america with the west coast of europe. east coast of africa. west coast of greenland. lower west coast of africa.

Which layer surrounds the center of the earth? a: crust b: core c: mantle