What do you need to study to become a mechanical engineer?

Derek is working on a thesis on the changes in social behavior in the context of finding partners. an important part of his study concerns the various practices followed by males and females over the course of generations and how they have gradually transformed into our current social norms. derek can be called a(n) psychologist. (tb75)\

Abrief, "first-step" presentation of a work to be completed is called a

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?