What does the word marginal in the term marginal revenue stand for?

Plz 20 ! in a citizens elect the president as head of government separately from the legislature? a: parliamentary democracy b: communist state c: presidential democracy d: autocratic state

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?

1u.s. history question! question: how did world war ii change the united states' position in world affairs? i need good explanation to support the answer otherwise i get docked points. real answers only ! you! : )