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Scattered through the seas of the world are billions of tones of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with currents, providing a basic food for many larger animals.
Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far out weights that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the sea’s plankton generates more than twice as much.
Despite its enormous food potential, little effort was made until recently to farm plankton as we farm grasses on land. Now marine scientists have begun to study this possibility, especially as the sea’s resources loom even more important as a means of feeding an expanding world population. Now one yet has seriously suggested that “planktonburgers” may soon become popular around the world. As a possible farmed supplementary food source, however plankton is gaining considerable interest among marine scientists.
One type of plankton that seems to have great harvest possibilities is a tiny shrimplike creature called krill. Growing to two or three inches long, krill provide the major food for the giant blue whale, the largest animals ever to inhabit the Earth. Krill swim about just below the surface in huge schools sometimes wide, mainly in the cold Antarctic. Because of the red pink color, they often appear as a solid reddish mass when viewed from the air. Krill are very high in food value: A pound of these crustaceans contains 460 calories, about the same as shrimp or lobster. If the krill can feed such huge creatures as whales, many scientists reason, they must certainly be contenders as a new food source for humans.
The author mentioned all of the following as reasons why plankton could be considered a human food source EXCEPT that it is
Ahigh in food value.
Bin abundant supply in the oceans.
Can appropriate food for animals.
Dfree from chemicals and pollutants.正確答案
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