In the United States, less than half as many multifamily housing units were produced in the 1990s than in each of the previous two decades.

Officials at the United States Mint believe that the Sacagawea dollar coin will be used more as a substitute for four quarters rather than for the dollar bill because of its weight, only 8.1 grams, which is far less than four quarters, which weigh 5.67 grams each.

Duckbill dinosaurs, like today's monitor lizards had particularly long tails, which they could whip at considerable speed. Monitor lizards use their tails to strike predators. However, although duckbill tails were otherwise very similar to those of monitor lizards, the duckbill’s tailbones were proportionately much thinner and thus more delicate. Moreover, to ward off their proportionately much larger predators, duckbills would have had to whip their tails considerably faster than monitor lizards do.

The information given, if accurate, provides the strongest support for which of the following hypotheses?

Although when a hagfish is threatened, it will secrete slime that is small in quantity, it expands several hundred times as it absorbs seawater, forming a slime ball that can coat the gills of predatory fish and either suffocate them or distress them enough to make them flee.

In the 1960s, surveys of Florida’s alligator population indicated that the population was dwindling rapidly. Hunting alligators was banned. By the early 1990s, the alligator population had recovered, and restricted hunting was allowed. Over the course of the 1990s, reports of alligators appearing on golf courses and lawns increased dramatically. Therefore, in spite of whatever alligator hunting went on, the alligator population must have increased significantly over the decade of the 1990s.

Which of the following, if true, most seriously weakens the argument?

Professor: A marine biologist argues that transmission of sea lice from farm salmon to wild salmon is unlikely in the Broughton Archipelago, British Columbia, citing numerous studies suggesting that salinities less than 30 parts per thousand are unfavorable to sea-lice survival. The biologist concludes that the archipelago's 25-30 parts per thousand salinity range between March and June, the critical period for wild salmon migration, tends to suppress sea-lice proliferation. But a review of the literature shows that salinities of 25-30 parts per thousand in combination with British Columbia's cool spring temperatures favor the flourishing of sea lice.

In this passage, the professor attempts to undermine the biologist's argument by

Dinosaur tracks show them walking with their feet directly under their bodies, like mammals and birds, not extended out to the side in the manner of modern reptiles.

By skimming along the top of the atmosphere, a proposed new style of aircraft could fly between most points on Earth in under two hours, according to its proponents.

Upon their first encountering leaf-cutting ants in South America, the insects seemed to some Europeans to be carrying bits of greenery to shade themselves from the tropical sun--hence the sobriquet "parasol ants.”

Although the earliest inhabitants of Mapungubwe, building their dwellings of either wattle and daub or unfired mud brick, by the thirteenth century buildings of coral blocks in lime mortar began to appear.