What factor(s) might influence family composition?

Children begin to use tools at about what age? a. 18 months b. 2 years c. 1 year d. 6 months

11. why do citizens have to register to vote?

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?