A. Define devolution and explain how one political process can result in
devolution.

Devolution, the transfer of power from a central government to subnational (e.g., state, regional, or local) authorities. Devolution usually occurs through conventional statutes rather than through a change in a country’s constitution; thus, unitary systems of government that have devolved powers in this manner are still considered unitary rather than federal systems, because the powers of the subnational authorities can be withdrawn by the central government at any time (compare federalism).

Explanation:

c. seafloor spreading occurs.

d. crust becomes molten rock.

e. denser plates slide under lighter plates.