What is at the center of a representative democracy?

Political parties are always at the center of a representative democracy.  Explanation:

Representative democracy is defined as the government system in which eligible citizens elect the representatives by voting to pass the law for them.  The advantage of this democracy is that peoples receive the benefits on a large scale and also equally in a proper way. This democracy also has the tag line that one person one vote. But it has many disadvantages such as fake voting, corruption.  The elected representative has the power on selecting the other legislature members and officers such as the president.