 What is one way the story’s setting, Venus, affects the characters and and sets up the plot?
DOUBLECROSS by JAMES Mac CREIGH Revolt was brewing on Venus, led by the descendant of the first Earthmen to land. [Transcriber's Note: This etext was produced from Planet Stories Winter 1944. The Executive Officer was moodily smoking a cigarette in the open lock, staring out over the dank Venusian terrain at the native town. But after all, they're human beings, just like us—" "Not any more. Four or five generations ago they were. "They had to acclimate themselves to Venus's climate. He stared at the wooden shacks that were the outskirts of the native city, dimly visible through the ever-present Venusian mist. The native guard of honor, posted a hundred yards from the Earth-ship, stood stolidly at attention with their old-fashioned proton-rifles slung over their backs. They think there will be hordes of immigrants from Earth, now that we know Venus is habitable. And there's some sort of a paltry underground group that is spreading the word that the immigrants will drive the native Venusians—the descendants of the first expedition, that is—right down into the mud. That's a basic law of—" The annunciator over the open lock clanged vigorously, and a metallic voice rasped: "Officer of the Deck! "From their own mouths you have heard it. Our parents came from Earth. "Then we must act. We have agreed that, if the Earth-ship returns, it means disaster for Venus. Therefore, it must not return."
 Over the last four or five generations, Venus’s conditions have caused its human colony to mutate in order to better survive. Differences in appearance cause a racial rift between humans from Earth and humans from Venus, which sets the story’s plot by imposing tension between the two groups.
 The story takes place on Mars, not Venus. Over the last four or five generations, Mars’ conditions have caused its human colony to mutate in order to better survive. This causes a racial rift between humans from Earth and humans from Mars, which sets the story’s plot by imposing tension between the two groups.  Over the last four or five generations, Venus’s conditions have caused its human colony to mutate in order to better survive. Differences in appearance cause a racial rift between humans from Earth and humans from Venus, which sets the story’s plot by imposing tension between the two groups.  Over the last fifteen generations, Venus’s conditions have caused its human colony to mutate in order to better survive. This causes a racial rift between humans from Earth and humans from Venus, which sets the story’s plot by showing Venusians in a bad light.  Over the last two or three generations, Venus’s conditions have caused its human colony to mutate into swamp people. This causes a holocaust of humans from Venus, which sets the story’s plot by imposing tension between the two groups.