Question

in general terms the heart of any representative democracy is

Answer 1

legislature i think

Answer 2

The Senate is a part of Congress, and Congress is a legislature, but it's not a "general term"--it's a specific term for the American federal legislature. Suffrage is not characteristic of *representative* democracy specifically.

Answer 3

"Democracy" implies people, citizens, and regular folks.
"Representative" implies they agree to speak through elected/appointed individuals.
Where does that put "the heart"? With the people or with the representative body?