1 There are two types of glial cells in the nervous system: the large-bodied macroglia and the smaller microglia. 2  There are two classes of macroglia in the central nervous system: astrocytes and oligodendrocytes.
Exports directly contribute and imports directly reduce their nation's balance of trade (i.e. net exports). A trade surplus is positive net balance of trade, and a trade deficit is a negative net balance of trade.
âThe trade deficit has been a thorn in the side of the U.S. economy for the past seven years.â âToday, by contrast, the current account deficit is larger than the trade deficit.â âIf exports exceed imports, there is a trade surplus and if imports exceed exports, there is a trade deficit.â âThus they ultimately contribute to growing budget and trade deficit and foreign debt.â