Which power does the federal government share with state governments

Which situation is an example of a citizen participating in a politicial process

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?

What conflict ended the false doctrine of "states rights"