question:  What makes Johnson's son so different?
context: [Transcriber's Note: This etext was produced from Planet Stories May 1943. Characteristically, Harvey Ellsworth tried to maintain his dignity, though his parched tongue was almost hanging out. He came near starving and moved on to Titan. It's bitter as some kinds of sin before it's purified. What's fair is fair, and you have put a different complexion on what seemed at first to be an unconscionable interjection of a middleman between Nature and man's thirst." Angus Johnson's my name. "On account of the quantity, I'm able to quote a bargain price. The planetoid man worked the pump while the mayor intently watched the crude level-gauge, crying "Stop!" when it registered the proper amount. Then Johnson rubbed his thumb on his index finger and wetted his lips expectantly. Johnson's response almost floored them. "Johnson, as I saw instantly, is the victim of a difficult environment, and must charge accordingly." "Just the same," Joe griped, "paying for water isn't something you can get used to in ten minutes." In the fragile forest, they soon came across a stream that sprang from the igneous soil and splashed into the small pond whose contents, according to the mayor, was theirs for the asking. It was on the sixth trip that Joe caught a glimpse of Jupiter-shine on a bright surface off to the left. He uses only one pool, the sweet one! Him and me are the whole Earthman population of Johnson City." Johnson's eight-foot son, topped by a massive roof of sun-bleached hair and held up by a foundation that seemed immovable, had obviously been born and raised in low gravity. For any decent-sized world would have kept him down near the general dimensions of a man. Harvey studied it worriedly, put his own hand somewhere on it, swallowed as it closed, then breathed again when his fingers were released in five units instead of a single compressed one.
output:  He grew up without Earth's gravity, allowing him to grow larger than most people.
options:  He grew up without Earth's gravity, allowing him to grow larger than most people.  He is much larger than the average man.  Like Genius, he is not human.  He's been living isolated from other humans with his father.