Which net change occurs in a nuclear fusion
reaction?
(1) ionic bonds are broken.
(2) ionic bonds are formed.
(3) energy is converted to mass.
(4) mass is converted to energy.

Mass is converted to energy as two smaller nuclei combine to form a larger nuclei with some of the mass being lost as energy.

That result from subduction of oceanic plates beneath lighter continental plates. most of the earth's volcanoes are located around the pacific ring of fire because that the location of most of the earth's subduction zones.