When young people migrate from a rural area which probably already is suffering from a low birthrate, this effectively eventually can create a "lack of life" in a certain place where after a decade or a few decades, a certain rural area can actually die out due to not enough young people being there anymore.
The Court established this doctrine in the case of Marbury vs. Madison in 1803.
The arid southwest where the ancestral puebloans existed comprised of southeastern Utah, northeastern Arizona, northwestern New Mexico and southwestern Colorado. Their knowledge of celestial sciences contributed to them adapting their housing to building materials available, like constructing small family grass-thatched pit houses and cliff-sited dwellings for defence. Some of them included grass and stone.