The economy

The economy is the one and only system by which money, industry, and trade are organized, nevertheless, the economy is the part of our life. When someone asks from us to image what is the economy, we simply think about money or how money works, but when they ask about money, we think about notes, coins, bills, or credit cards. So when and why money was created? What is the economy, is it money or the system? Why do we need аn economy? Although, we know the answer for these questions, we always misunderstand the actual meaning of these statements.