Brown tides are growths of algae on the sea's surface that prevent sunlight from reaching marine plants below, thereby destroying not only the plants but also the shellfish that live off these plants. Biologists recently isolated a virus that, when added to seawater, kills the algae that cause brown tides. Adding large quantities of this virus to waters affected by brown tides will therefore make it possible to save the populations of shellfish that inhabit those waters.

Which of the following, if true, provides the most support for the conclusion of the argument?

The cactus is now heavily plundered in deserts in the southwestern United States, so much that enforcement agencies in five states have created special squads for its protection.

Highway Official: When resurfacing our concrete bridges, we should use electrically conductive concrete (ECC) rather than standard concrete. In the winter, ECC can be heated by passing an electric current through it, thereby preventing ice buildup. The cost of the electricity needed is substantially lower than the cost of the deicing salt we currently use.

Taxpayer: But ECC is vastly more expensive than standard concrete, so your proposal is probably not justifiable on economic grounds.

Which of the following, if true, could best be used by the highway official to support the official's proposal in the face of the taxpayer's objection?

Manufacturers of mechanical pencils make most of their profit on pencil leads rather than on the pencils themselves. The Write Company, which cannot sell its leads as cheaply as other manufacturers can, plans to alter the design of its mechanical pencil so that it will accept only a newly designed Write Company lead, which will be sold at the same price as the Write Company's current lead.

Which of the following, if true, most strongly supports the Write Company's projection that its plan will lead to an increase in its sales of pencil leads?

The company’s CEO backed away from her plan for dividing the firm into five parts, saying that she still had meant to spin off or sell two units but that the company would retain ownership of two others as well as the core company.

Once made exclusively from the wool of sheep that roam the Isle of Lewis and Harris off the coast of Scotland, Harris tweed is now made only with wools that are imported, sometimes from the mainland and sometimes they come--as a result of a 1996 amendment to the Harris Tweed Act--from outside Scotland.

To show that it is serious about addressing the state's power crisis, the administration has plans for ordering all federal facilities in California to keep thermostats at 78 degrees Fahrenheit and shutting down escalators during electricity shortages this summer.

The market for so-called functional beverages, drinks that promise health benefits beyond their inherent nutritional value, nearly doubled over the course of four years, in rising from $2.68 billion in 1997 to be $4.7 billion in 2000.

Pretzel Vendor: The new license fee for operating a pretzel stand outside the art museum is prohibitively expensive Charging typical prices. I would need to sell an average of 25 pretzels per hour to break even. At my stand outside City Hall, with about as many passers-by as at the art museum, I average only 15 per hour. So I could not break even running a stand outside the art museum, much less turn a proft.

Which of the following, if true, most seriously weakens the pretzel vendor's argument?

It can be inferred from the passage that a multinational manufacturing company that was attempting to become a multicultural multinational would be most likely to