Biologists with a predilection for theory have tried—and largely failed—to define what it is that makes something a living thing. Organisms take in energy-providing materials and excrete waste products, but so do automobiles. Living things replicate and take part in evolution, but so do some computer programs. We must be open to the possibility that there are living things on other planets. Therefore, we will not be successful in defining what it is that makes something a living thing merely by examining living things on Earth—the only ones we know. Trying to do so is analogous to trying to specify __________.
Which of the following most logically completes the passage?

Last year a record number of new manufacturing jobs were created. Will this year bring another record? Well, any new manufacturing job is created either within an existing company or by the start-up of a new company. Within existing firms, new jobs have been created this year at well below last year’s record pace. At the same time, there is considerable evidence that the number of new companies starting up will be no higher this year than it was last year and there is no reason to think that the new companies starting up this year will create more jobs per company than did last year’s start-ups. So clearly, the number of new jobs created this year will fall short of last year’s record.
In the argument given, the two portions in boldface play which of the following roles?

Last year a record number of new manufacturing jobs were created. Will this year bring another record? Well, any new manufacturing job is created either within an existing company or by the start-up of a new company. Within existing firms, new jobs have been created this year at well below last year’s record pace. At the same time, there is considerable evidence that the number of new companies starting up this year will be no higher than it was last year and there is no reason to think that the new companies starting up this year will create more jobs per company than did last year’s start-ups. So clearly, the number of new jobs created this year will fall short of last year’s record.
In the argument given, the two portions in boldface play which of the following roles?

In response to viral infection, the immune systems of mice typically produce antibodies that destroy the virus by binding to proteins on its surface. Mice infected with the herpes virus generally develop keratitis, a degenerative disease affecting part of the eye. Since proteins on the surface of cells in this part of the eye closely resemble those on the herpes virus surface, scientists hypothesize that these cases of keratitis are caused by antibodies to the herpes virus.
Which of the following, if true, most helps to support the scientists’ reasoning?

The city of Workney, in raising bus fares from $1.00 to $1.25, proposed that 18 fare tokens be sold for $20.00 to alleviate the extra burden of the fare increase on the city’s poor people.Critics suggested alternatively that 9 fare tokens be sold for $10.00, because a $20.00 outlay would be prohibitive for poor riders.
The alternative proposal depends on which of the following assumptions?

A company has developed a new sensing device that, according to the company’s claims, detects weak,ultralow-frequency electromagnetic signals associated with a beating heart.These signals, which pass through almost any physical obstruction, are purportedly detected by the device even at significant distances. Therefore, if the company’s claims are true, their device will radically improve emergency teams’ ability to locate quickly people who are trapped within the wreckage of collapsed buildings.
Which of the following, if true, most strengthens the argument?

A prominent investor who holds a large stake in the Burton Tool Company has recently claimed that the company is mismanaged, citing as evidence the company’s failure to slow down production in response to a recent rise in its inventory of finished products. It is doubtful whether an investor’s sniping at management can ever be anything other than counterproductive, but in this case,it is clearly not justified. It is true that an increased inventory of finished products often indicates that production is outstripping demand, but in Burton’s case it indicates no such thing. Rather, the increase in inventory is entirely attributable to products that have already been assigned to orders received from customers.
In the argument given, the two boldfaced portions play which of the following roles?

Enforcement of local speed limits through police monitoring has proven unsuccessful in the town of Ardane. In many nearby towns, speed humps (raised areas of pavement placed across residential streets,about 300 feet apart) have reduced traffic speeds on residential streets by 20 to 25 percent. In order to reduce traffic speed and thereby enhance safety in residential neighborhoods, Ardane’s transportation commission plans to install multiple speed humps in those neighborhoods.
Which of the following, if true, identifies a potentially serious drawback to the plan for installing speed humps in Ardane?

Last year a record number of new manufacturing jobs were created. Will this year bring another record? Well, any new manufacturing job is created either within an existing company or by the start-up of a new company. With in existing firms, new jobs have been created this year at well below last year’s record pace. At the same time, there is considerable evidence that the number of new companies starting up will be no higher this year than it was last year and there is no reason to think that the new companies starting up this year will create more jobs per company than did last year’s start-ups. So clearly, the number of new jobs created this year will fall short of last year’s record.

In the argument given, the two portions in boldface play which of the following roles?

Boreal owls range over a much larger area than do other owls of similar size. Scientists have hypothesized that it is scarcity of prey that leads the owls to range so widely. This hypothesis would be hard to confirm directly, since it is not possible to produce a sufficiently accurate count of the populations of small mammals inhabiting the forests where boreal owls live. Careful study of owl behavior has, however, shown that boreal owls do range over larger areas when they live in regions where food of the sort eaten by small mammals is comparatively sparse. This indicates that the scientists’ hypothesis is not sheer speculation.
In the argument given, the two boldfaced portions play which of the following roles?