What is a referendum and why is it an important tool in or democratic system?

Political science here!

Explanation:

The REFERENDUM allows citizens, through the petition process, to refer acts of the Legislature to the ballot before they become law. ... The primary purpose of both is to give voters an opportunity to approve or reject laws either proposed or enacted by the Legislature.

A referendum (plural: referendums or less commonly referenda) is a direct vote by the electorate on a particular proposal or issue. This is in contrast to an issue being voted on by a representative. It can have nationwide or local forms. This may result in the adoption of a new policy or specific law.