How did the crusades. lead to the creation of modern european nation states

Greg goes to a high school and observes the way students talk to each other. he makes notes on the words used, the atmosphere of the school and the way the students present themselves to each other. this is an example of a( research method.

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

Carbon tetrachloride is a toxic liquid. a carbon tetrachloride molecule has one atom of carbon and four atoms of chlorine. what is its chemical formula?