Roberto makes a graphic organizer to compare fusion nuclear reactions and fission nuclear reactions. which labels belong in the regions marked x, y, and z? x: smaller nuclei form y: thermal energy is produced z: a larger nucleus forms x: large amounts of energy are released y: one or more neutrons is released z: smaller nuclei form x: one or more neutrons is released y: a larger nucleus forms z: large amounts of energy are released x: a larger nucleus forms y: large amounts of energy are released z: smaller nuclei form