during nuclear fission and fusion, what is matter that seems to disappear actually converted…

during nuclear fission and fusion, what is matter that seems to disappear actually converted into?\nmass\nenergy\nvolume\nnuclei
Answer
Brief Explanations:
According to Einstein's mass - energy equivalence principle ($E = mc^{2}$), in nuclear fission and fusion, the mass that appears to be lost is converted into energy.
Answer:
energy