Medical columnist: Some doctors recommend taking vitamin C to help maintain overall health because vitamin C is an antioxidant, a substance that protects the body from certain types of oxygen particles that can trigger disease. People suffering from various ailments are encouraged to take vitamin C to guard against developing other health problems. However, doctors are now discouraging some cancer patients from taking vitamin C, even when they are undergoing therapies with side effects that are detrimental to their overall health.
"Surprising" Phenomenon
Why do doctors discourage some cancer patients from taking vitamin C, even though some doctors encourage people suffering from other illnesses to take vitamin C to guard against developing other health problems?
Objective
The correct answer should help suggest how taking vitamin C might be negative for cancer patients, even if it’s helpful for patients with other illnesses.
A
Some kinds of cancer cells absorb large amounts of vitamin C, which interferes with the oxidation mechanism by which many cancer therapies kill cancer cells.
This helps show that vitamin C could be negative for cancer patients. If some cancer cells interfere with cancer therapies by absorbing lots of vitamin C, taking vitamin C might undermine the effectiveness of cancer therapies.
B
Vitamin C has not been shown to reduce people’s risk of developing cancer, even at the very high dosage levels recommended by some doctors.
Vitamin C is recommended because it helps guard against developing “other health problems.” So, even if it doesn’t help with cancer, it can still guard against other illnesses in a cancer patient. We’d still expect doctors to recommend vitamin C to cancer patients.
C
Cancer cells that are susceptible to certain types of cancer therapies are not likely to be affected by the presence of vitamin C.
Vitamin C is recommended because it helps guard against developing “other health problems.” Even if it doesn’t help with killing cancer cells, it can still guard against other illnesses in a cancer patient. We’d still expect doctors to recommend vitamin C to cancer patients.
D
The better the overall health of cancer patients while undergoing therapy, the more likely they are to experience a full recovery.
This doesn’t tell us anything about vitamin C or how it might affect cancer patients.
E
Certain side effects of cancer therapies that are detrimental to patients’ overall health are not affected by vitamin C.
Vitamin C is recommended because it guards against developing “other health problems.” Even if it doesn’t help with side effects of therapies, it can still guard against other illnesses in a cancer patient. We’d still expect doctors to recommend vitamin C to cancer patients.
A
Mechanical monitoring devices have not already been installed in areas where air pollution is a serious problem.
B
Copper particles are a component of air pollution in several locales.
C
Experiments have shown that lichens thrive in areas where air pollution is minimal.
D
Lichens can easily be grown in laboratories.
E
Lichens absorb all other significant air pollutants in a manner similar to their absorption of copper.
A
Neither migratory birds nor humans have an innate homing sense.
B
There is as yet little reason to accept that birds have an innate homing sense.
C
Studies testing whether the accuracy of birds’ migratory patterns is due to an innate homing sense are inconclusive.
D
The ability to use landmarks to find one’s way home is probably not an innate ability in birds.
E
It is as false to claim that humans have an innate sense of direction as it is to claim that birds have an innate homing sense.
All laundry detergents contain surfactants, which can harm aquatic life. However, the environmental effects of most ingredients in laundry detergents, including most of those in so-called “ecologically friendly” detergents, are unknown. Therefore, there is no reason to suppose that laundry detergents advertised as ecologically friendly are less damaging to the environment than other laundry detergents are.
Summarize Argument
The author concludes that there is no reason to believe that laundry detergents advertised as “eco-friendly” are less damaging to the environment than other laundry detergents are. He supports this by saying that the environmental effects of most laundry detergent ingredients, including most ingredients in “eco-friendly” detergents, are unknown.
Notable Assumptions
The author assumes that because the environmental effects of most detergent ingredients are unknown, there is no reason to believe that "ecologically friendly" detergents are less damaging. This ignores the possibility there could be some other reason to believe that eco-friendly detergents are less damaging, such as the effects of those ingredients that are known, or the effects of some other factor like packaging or production.
A
Laundry detergents that are advertised as ecologically friendly contain much lower amounts of surfactants, on average, than do other laundry detergents.
If “eco-friendly” detergents contain much lower amounts of environmentally damaging surfactants than other detergents, this gives a reason to believe that they might be less damaging to the environment, even though the effects of most of their ingredients are unknown.
B
There is no reason to suppose that most of the ingredients in laundry detergents not advertised as ecologically friendly harm the environment significantly.
The columnist’s argument is about the environmental effects of those detergents that are advertised as eco-friendly. Whether or not there is reason to believe that regular laundry detergents harm the environment doesn’t weaken her conclusion about “eco-friendly” detergents.
C
Different kinds of laundry detergents contain different kinds of surfactants, which differ in the degree to which they could potentially harm aquatic life.
This is too vague to weaken the columnist’s conclusion because we don’t know which kinds of detergents contain which kinds of surfactants. Do “eco-friendly” detergents contain more harmful or less harmful surfactants? (C) doesn’t give us this information.
D
There is reason to suppose that ingredients in laundry detergents other than surfactants harm the environment more than surfactants do.
Like (C), this is too vague to impact the columnist’s argument. We don’t know which detergents contain these other, more harmful ingredients, so we can’t conclude anything about the effects of “eco-friendly” detergents.
E
Laundry detergents advertised as environmentally friendly are typically less effective than other detergents, so that larger amounts must be used.
If larger amounts of “eco-friendly” detergents must be used and these detergents contain harmful surfactants, (E) strengthens the columnist’s conclusion that there is no reason to believe that “eco-friendly” detergents are less damaging to the environment than other detergents.
A
Draining the lake would not cause the region’s tourism economy to suffer.
B
Four years ago was the only time that poison was used against the pike in the lake.
C
The poison added to the lake four years ago was not successful in ridding the lake of the pike.
D
Four years ago, fishery officials did not consider any options other than using poison.
E
Salmon and trout populations in the Lake Davis area are essential to the region’s economy.
A
Many people assume that personal conflicts are inevitable.
B
Even when there is more evidence of good qualities than of bad ones, people find it easier to ascribe bad qualities than good ones.
C
It is irrational to allow a single instance to turn one’s suspicion that a friend is unreliable into a feeling of certainty.
D
Personal conflicts are not inevitable.
E
Unlike a suspicion that a friend is unreliable, a belief that someone is reliable is normally built up only after many years of personal interaction.
A
During the 800-year period studied, seal hunting practices did not vary substantially between different groups of Native peoples in North America.
B
The body size of northern fur seals is not strongly correlated with the overall health of the seals.
C
Before the 800-year period studied, the average body size of northern fur seals fluctuated dramatically.
D
Native peoples in North America made an effort to limit their hunting of northern fur seals in order to prevent depletion of seal populations.
E
Hunting by Native peoples in North America did not significantly reduce the northern fur seal population over the 800-year period studied.
Mayor: Our city faces a difficult environmental problem caused by the enormous amount of garbage that we must dispose of. Although new recycling projects could greatly reduce this amount, these projects would actually be counterproductive to the goal of minimizing the overall amount of environmental damage.
"Surprising" Phenomenon
Why would new recycling projects be counterprodutive to the goal of minimizing environmental damage, even though the high amount of garbage produced by the city causes environmental damage and the recycling projects would reduce the amount of garbage?
Objective
The correct answer will suggest some way that new recycling projects could lead to more overall environmental damage than forgoing those recycling projects. Perhaps, for example, new recycling projects end up harming the environment in other ways, even if they help by reducing the amount of garbage.
A
The vehicles that pick up materials for recycling create less pollution than would be caused by incinerating those materials.
We don’t know whether incineration is part of the new recycling projects. But even if it were, (A) suggests incineration could produce less environmental damage than the current recycling method. So, we’d still expect new recycling projects to produce less overall damage.
B
The great costs of new recycling projects would prevent other pollution-reducing projects from being undertaken.
Other pollution-reducing projects might reduce damage even more than the new recycling projects. If the new recycling projects prevent us from doing those other projects, this could be why the new recycling projects would be counterproductive.
C
The mayor’s city has nearly exhausted its landfill space and therefore must incinerate much of its garbage.
Is incineration a new recycling project? If it isn’t, it has no clear impact. If it is, then the lack of landfill space suggests incineration could be good for the environment. (C) doesn’t tell us something potentially negative about the new recycling projects.
D
More recycling would give industries in the mayor’s city a greater incentive to use recycled materials in their manufacturing processes.
If anything, this answer suggests another benefit of new recycling projects. That doesn’t help explain why new recyling projects could lead to more overall environmental damage.
E
People who recycle feel less justified in consuming more than they need than do people who do not recycle.
If anything, this suggests another benefit of new recycling projects. If we can get people to recycle, they might not use as many resources, which might be good for the environment. This doesn’t help explain why new recycling projects could lead to more environmental damage.