Aresearcher reports a positive relationship between sugar consumption and activity level for a group of 8-year-old children. however, the researcher cannot be sure whether the extra sugar is causing the children to be more active or whether the extra activity is causing the children to eat more sugar. this is an example of the

This is the mountain range known as the alps. which of these statements regarding the alps is true? a) the alps are the largest mountain range in asia. b) the alps protect the roman empire from invasion. c) the alps were key in preventing england from being conquered in warfare. d) the alps prevented the roman empire from taking control of most of europe.

As of 2013, the world’s total population was about

Predict how the transcontinental railroad will make a difference in the civil war. now, research the inventions of the 19th century. tell what other inventions of the 19th century will change the way people see and remember the war? why?