What does rural and urban mean

When employing the core learning system, reading text books and attending class are important ways to knowledge.

Chen's research team randomly assigned some newborns and their mothers either to a breastfeeding promotion group (where breastfeeding was encouraged, but not required) or to a normal pediatric care group (where breastfeeding was neither encouraged nor discouraged). which research method did they use?

If we can't separate our civilized self from our savage self which will take over and why