What in addition to geographic boundaries might have kept the people of the huang river civilization from traveling to far distance region

Read the excerpt from the monsters are due on maple street.as they suddenly start toward the house. in this brief fraction of a moment they take the first step toward performing a metamorphosis that changes people from a group into a mob. they begin to head purposefully across the street toward the house at the end. steve stands in front of them. for a moment their fear almost turns their walk into a wild stampede but steve's voice, loud, incisive and commanding, makes them stop.stevewait a minute . . wait a minute! let's not be a mob! the people stop as a group, seem to pause for a moment and then much more quietly and slowly start to walk across the street.which sentence from the excerpt is an example of foreshadowing? a) as they suddenly start toward the house.b) in this brief fraction of a moment they take the first step toward performing a metamorphosis that changes people from a group into a mob.c) they begin to head purposefully across the street toward the house at the end.d) the people stop as a group, seem to pause for a moment and then much more quietly and slowly start to walk across the street.