Other contributors have said "Rights and responsibilities in a democracy?" is the same question as "What is the defining right of a representative democracy?" If you believe that these are not asking the same thing and should be answered differently, click here
What is the defining right of a representative democracy?
The rights and responsibilities of a citizen living in a representative democracy is to tell the "representer" what concerns them or is an issue, and they will try to get it solved :)
Representative democracy is a democracy where the people choose a representative to represent them in the government. This representative will then vote for the things the people he represents want.
Democracy is a political concept. Democracy is subdivided into two forms---representative and direct. If you're talking about the federal government, then the US is a representative...