nuclear fusion increases the mass through fusing two nuclei together into one & nulear fusion releases a large amount of energy & nuclear fusion is a kind of process ->  nulcear fusion is a process that fuses two nuclei into one and releases large amount of energy  nulcear fusion is a process that fuses two nuclei into one and releases large amount of energy & a process combines two nuclei into one and releases a large amount of energy -> the process is nulcear fusion