Francine rolled a marble down a ramp and timed how long it took for the marble to reach the bottom of the ramp. After one trial, she doubled the height of the ramp and added a thick layer of wool cloth to the surface of the ramp. She conducted three more trials and after reviewing the data, Francine concluded that the height of the ramp had no effect on the speed of the marble rolling down the slope. Which of the following reasons best describes why her conclusion is unsupported?

Both the han and the roman empire decline as a result of social unrest during their collapse.

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.