Does the U.S. system reflect the benchmarks of representative democracy?
This is hard to answer without knowing what your text says the benchmarks of representative democracy are.
I would say that the US system imperfectly reflects what I see as the benchmarks of representative democracy. I say this because I believe that the people do have the power to elect their officials but, at the same time, they do not have much of an ability to speak on specific issues of policy.
When our leaders run for office, they do not have to promise to do specific things. They do not run on some set party platform that will be put into place if their party wins. Instead, they tend to run based on platitudes (we want small government, less corruption, less waste) that do not really mean much of anything in particular. When we vote for them, it is not clear what we are voting for -- they have not set out some specific agenda.
So we do get to vote. But the meaning of our votes is not clear and so we do not really get to elect representatives who are bound to carry out policies that we want.