One of the disadvantages of operating a barter system is that trading is

Disadvantages are that bartering frequently requires much time and hassle and that goods are often not readily divisible, meaning that swapped goods have to be basically equal in value if a trade is to occur.

Explanation:

balearic sea - is a body of water in the mediterranean sea around the balearic islands. baltic sea - is a mediterranean sea of the atlantic which is enclosed by scandinavian and baltic countries. barents sea - is a marginal sea in the artic ocean located off the northern coast of norway and russia.

well, there are a lot of places we get information about earth from. like science classes, websites, books, newspapers, etc.