What are financial intermediaries? How do these intermediaries function in the economy?

Assignment 1: Financial Concepts

Your niece just started her college career with a major in economics. She is curious as to the interrelationship between the success of an economy and the financial markets, concepts, and financial institutions. Accordingly, she has developed a list of questions addressing these issues and has asked that you explain the ideas.

What are the financial markets and what purposes do they serve?
What are financial intermediaries? How do these intermediaries function in the economy?
What is a federal government budget deficit? What is the national debt? How does a budget deficit affect the economy?