51.   He reports that the chemical is concentrated in the topmost layers of seawater -- home to the plankton which feed larger marine animals.

52.   Within the United Kingdom, the population is heavily concentrated in one country.

53.   Services currently available in all districts could be concentrated in just one hospital and patients might have to travel many miles for treatment, it was feared.

54.   Its stores are concentrated primarily in the north and east of Scotland.

55.   The problem was that OPEC was likely to lend mainly in US markets whereas the potential borrowers were concentrated in Europe and the Third World.

56.   The operations of commercial banks in LDCs, however, are concentrated in major cities and towns.

57.   Already, defense work has become concentrated in far fewer hands.

58.   Although hundreds of hospitals treat some AIDS patients, much of the activity was concentrated in a few.

59.   Although Mexican migrants do planting as far north as Maine and Washington state, they are concentrated in the South.

60.   Although the economy is growing, the new wealth is concentrated in the cities.