Oral stories only made sense, although Trunks wanted to believe there had to be some scientists and others among his people. How else would the race survive as a whole? "Generations?" This got his brain turning as he thought that over.
"How long do we live then? Roughly?" He already knew his Father was older than he looked, as was Goku.
No it really doesn't.
"How long do we live then? Roughly?" He already knew his Father was older than he looked, as was Goku.