1a. A U.S. penny meets all the functions of money and count as money in U.S economy. Because it is used as medium of exchange to buy other goods and services.
b. A Mexican peso is not in the U.S economy, because it is not a medium of exchange, but it could use as a store of value.
c. A Picasso painting is not in the three functions of money in the U.S because it cannot exchange for goods or services, and this can use for a store of value.
d. A credit card is not in any of the three functions of money in the U.S, it is like money, but it is only a short-term use rather than real money/ currency.
4. If this $100 stay in the banking system as reserves and if the banks hold reserves equal to 10 percent of deposit, it will increase by $1000. And