Whats one way the presidential elections changed over the years

Which choice best describes the general trend for the countries shown, for the period 2008 - 2010?

He constitution dictates that the presiding officer of the senate is the a) majority whip. b) vice-president. c) majority leader. d) speaker of the house.

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?