Imagine you were a west african ruler 500 years ago. what would you do to your empire grow that you might have learned from the empires of ghana, mali, and songhai?

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?