What is the basic difference between a nuclear fission reaction and a nuclear fusion reaction? a) fusion is a synthesis reaction while fission is a decomposition reaction. b) fusion is an exothermic reaction while fission is an endothermic reaction. c) fusion does not generate energy while fission generates a huge amount of energy. d) fusion only takes place in the stars so it cannot be used on earth to generate energy while fission can be used here for energy.