 Why is the story's setting important for the plot?
Yet I had always been so sure I could create them that I had been calling them volplas for ten years. Again in the laboratory, I entered the metabolic accelerator and withdrew the intravenous needles from my first volplas. The accelerator had forced them almost to adulthood in less than a month. It would be several hours before they would begin to move, to learn to feed and play, perhaps to learn to fly. Meanwhile, it was clear that here was no war of dominant mutations. I wiped the back of my hand across my mouth and said aloud, "Yes, sir, the dangerous age. Outside this little town, I found a litter of flat stones that had young black-snakes under each slab.
 The narrator's ranch is so big it can conceal its inhabitants.
 The narrator's ranch is so big it can conceal its inhabitants.  The volplas can only survive in California.  There are sparrows for the volplas to eat at the narrator's ranch.  The volplas originally lived in a similar landscape.