Until 1973 homosexuality was considered a psychological disorder american psychological association. which sociological perspective would be most concerned with why this was considered an illness, and what effect that diagnosis had on society?

The answer is Symbolic interactionist.
Symbolic interactionist refers to a sociological perspective which attempts to understand how individuals interact with one another using symbolic gestures and how it could contribute to the formation of pragmatism method to analyze social situations (such as same sex relationship)

Currently, as of february 2016, an american traveling in france would be by the exchange rate. the weakness of the euro and the strength of the us dollar means that items in france cost less to an american than they otherwise would. of course, if this trend reverses and the us dollar weakens and the euro strengthens, such as was happening in early 2008, an american traveling in france would have an adverse experience because items would cost relatively more.