Cowrie shells used for centuries as a medium of exchange are an example of:

1. Money has taken many physical forms. 2. Money has taken a wide variety of forms in different cultures. 3. For centuries people used the durable cowrie shell as a medium of exchange. 4. Items used as commodity money also have a value from use as something other than money. 5. A shell is such an item, so it is commodity money. _Source: OpenStax Principles of Macroeconomics for AP Courses 2e (CC BY 4.0), Ch 13 'Money and Banking'_