What-are-the-functions-of-political-parties-and-how-do-these-functions-strengthen-democracy

After reading the chapter: “Interest Groups and Political Parties” and attending lecture follow the instructions below.
Answer the question: What are the functions of political parties, and how do these functions strengthen democracy? List and explain three functions discussed in the textbook and in lecture, then explain how these functions fulfills democracy. Try to find real life examples to support your argument.
Be cautious with this assignment. I am not asking about Democrats or Republicans. The question is about political parties in general.
450 to 500 words