Why is the national integrity of subject of National Concern​

Which of the following contributed most to making the items listed in the box

If i see a courtesan and a naked person do i call the police?

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?