Question

which is an advantage of using modern currency instead of a barter system?
risk of a loss in value or counterfeiting
difficulty in determining the value of goods
ability to store and use a form that is accepted everywhere
a limited amount of goods and services available

Explanation:

Modern currency is a widely - accepted medium of exchange. It can be stored easily (e.g., in bank accounts, wallets) and is accepted in a large number of places (domestically and, in the case of some major currencies like the US dollar, internationally). In a barter system, goods are exchanged directly. There is no standard unit of account, so determining the value of goods (e.g., how many apples equal one sheep) is difficult. Also, bartered goods (like perishable food) may not be easily stored. The risk of loss in value (e.g., inflation for currency, but more relevant to currency's stability rather than an advantage over barter) or counterfeiting is a drawback of currency, not an advantage. A limited amount of goods and services available is not an advantage of currency over barter.

Answer:

ability to store and use a form that is accepted everywhere