during nuclear fission and fusion, what is matter that seems to disappear actually converted into?\no…

during nuclear fission and fusion, what is matter that seems to disappear actually converted into?\no mass\no energy\no volume\no nuclei
Answer
Brief Explanations:
According to Einstein's mass - energy equivalence (E = mc²), in nuclear fission and fusion, the mass that appears to be lost is converted into energy.
Answer:
B. energy