Mark is a researcher interested in understanding whether anxiety is related to sleep. Mark designs a research study where he will ask participants to report their level of anxiety on the day of the study and then, on the following day, they will report the number of hours they slept the night before (i. e., the night of the study). Mark hypothesizes that higher anxiety during the day will be associated with fewer hours slept that night. It sounds like Mark's research design is .

Which statement from the excerpt shows that president obama believes it is the president's duty to ensure that native american nations are involved in the democratic process? a. "when anybody in this country is not being treated equally under the law . . it's my job as president to solve it." b. "i made it a point to meet with tribal leaders . . because i wanted to make sure our country did better by our first americans." c. "i wanted to change the relationship between our governments—to elevate your voices in washington and give your tribes greater say over the decisions that affect the lives of your people every day." d. "and i wanted to turn the page on a history that is riddled with too many broken promises, [and] write a new chapter with a spirit of respect and trust."