How many angels can dance on the head of a pin?

How has the immigration of the 1990s affected the social and economic life of the united states?

What is the rule relating the ratio of marginal utility to prices of two goods at the optimal choice? explain why, if this rule does not hold, the choice cannot be utility-maximizing.

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?