PLEASE SOMEONE HELPPP WHAT US THE CORRECT ONE??

Lava and other matierls luanced from a volcano and into the air are referenced as

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 is “the compromise of 1850? ” *