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.
The term balance of payments surplus (or deficit â a deficit is simply a negative surplus) refers to the sum of the surpluses in the current account and the narrowly defined capital account (excluding changes in central bank reserves).