Zebra mussels, a nuisance when they clog the intake pipes of nuclear power plants and water plants along the Great Lakes, have some redeeming qualities. Since the mussels feed voraciously on algae that they filter from the water that passes by them, bags of zebra mussels suspended in the discharge streams of chemical plants significantly improve water quality, even removing some hazardous wastes. Which one of the following is most strongly supported on the basis of the statements above, if they are true? ['There is no mechanical means available for clearing intake pipes by scraping the mussels from them.', 'Zebra mussels arrived in the Great Lakes on transatlantic freighters and, since they have no natural enemies there, are rapidly displacing the native species of clams.', 'If the mussels spread to areas of the Mississippi River where native clams provide the basis for a cultured-pearl industry, that industry will collapse, since the mussels are unsuitable for such use and would displace the clams.', 'Any hazardous waste the mussels remove from chemical-plant discharge will remain in the mussels, if they do not transform it, and they then must be regarded as hazardous waste.']