Opponent: The irradiation process has no effect on the bacteria that cause botulism, a very serious form of food poisoning, while those that cause bad odors that would warn consumers of botulism are killed. Moreover, Salmonella and the bacteria that cause botulism can easily be killed in poultry by using a safe chemical dip.
Summarize Argument
The proponent concludes that there’s no reason to reject irradiation on the grounds of nutrition or safety. As support, he gives four claims:
(1) Irradiation prevents food from spoiling before reaching stores.
(2) It leaves behind no radiation.
(3) Vitamin loss from irradiation and from cooking are the same.
(4) It kills harmful Salmonella bacteria.
Identify and Describe Flaw
Per the question stem, we need to find the gap between claim (3) above and the conclusion that irradiation shouldn’t be rejected for nutritional or safety reasons.
The author assumes that since irradiation and cooking cause the same amount of vitamin loss, irradiation shouldn’t be rejected for nutritional reasons. But what if you cook irradiated food? Wouldn’t it have twice as much vitamin loss? Or if you don’t cook it, wouldn’t it still have more vitamin loss than non-irradiated raw food?
A
After irradiation, food might still spoil if kept in storage for a long time after being purchased by the consumer.
This is an issue with consumers’ storage practices, not with irradiation. Also, the author only claims that irradiation prevents food from spoiling before it reaches stores. He doesn’t say anything about it spoiling after it’s purchased. (A) also fails to address vitamin loss.
B
Irradiated food would still need cooking, or, if eaten raw, it would not have the vitamin advantage of raw food.
The author assumes that since irradiation and cooking cause the same vitamin loss, irradiation shouldn’t be rejected for nutrition reasons. But if irradiated foods are cooked, they lose twice the vitamins. And if eaten raw, they’ve already lost more vitamins than other raw food.
C
Vitamin loss is a separate issue from safety.
This may be true, but the proponent’s conclusion addresses safety and nutrition. Vitamin loss is surely included in nutrition.
D
Vitamins can be ingested in pill form as well as in foods.
This may be true, but the argument just addresses vitamin loss due to irradiation. Even if one can still take vitamin supplements, it doesn’t impact the argument that irradiation shouldn’t be rejected for nutritional reasons because it causes the same vitamin loss as cooking.
E
That food does not spoil before it can be offered to the consumer is primarily a benefit to the seller, not to the consumer.
This may be true, but it doesn't address vitamin loss, nor does it impact the argument. The argument is just about whether or not there’s grounds to reject irradiation. It doesn’t matter who benefits from the food not spoiling.
Summarize Argument
The author concludes that standard archeology cannot measure the ages of ancient paintings on limestone. Why? Because carbon always comes along with vegetable-based paint samples collected from limestone, and anything with carbon and vegetable matter can’t be aged using standard techniques.
Notable Assumptions
The author assumes that neither vegetable matter nor carbon can be removed from the samples after collection. If either material can be separated out, then the remaining paint would not be restricted by the author’s general rule and standard techniques may be usable.
A
There exist several different techniques for collecting samples of prehistoric pigments on limestone.
The author states that all such techniques involve removing limestone. This does not imply that any method allows paint to be collected without carbon coming along.
B
Laboratory procedures exist that can remove all the limestone from a sample of prehistoric paint on limestone.
This disputes the assumption that the samples must retain their carbon. If limestone can be removed, then the carbon-free paint can be isolated and may be measurable using standard techniques.
C
The age of the limestone itself can be determined from samples that contain no vegetable-based paint.
This suggests a method to determine the limestone’s age, not the paint’s age. The author does not say that knowing the limestone’s age allows archaeologists to know the paint's age.
D
Prehistoric artists did not use anything other than vegetable matter to make their paints.
This does not imply the samples are free of carbon, since the carbon comes from the limestone. It eliminates the possibility that vegetable matter can be separated from the remaining paint, thus strengthening the argument.
E
The proportion of carbon to other elements in limestone is the same in all samples of limestone.
This implies the amount of carbon in a sample can be known, not that it can be removed. The author states that the presence of carbon, not the variability of carbon, makes standard techniques unusable.
Summarize Argument
The author concludes paper products currently hurt the country’s environment more than plastic products. Why? Because paper trash and plastic trash do roughly the same damage, but there’s more paper trash out there, by weight and by volume.
Notable Assumptions
The author assumes there’s nothing else about plastic or paper that makes plastic products more harmful to the environment. This means assuming that plastic does no more harm than paper over a given product’s entire life cycle, including before it becomes garbage.
A
A given weight of paper product may increase in volume after manufacture and before being discarded as trash.
This doesn’t affect the argument. It doesn’t say paper does more or less harm—or exists in greater or lesser amounts—at earlier stages of its life cycle than plastic does.
B
According to popular opinion, volume is a more important consideration than weight in predicting the impact of a given quantity of trash on the environment.
This doesn’t affect the argument. The study found more paper than plastic by weight and by volume, so the conclusion is supported equally whether this is true or false.
C
The sum of damage caused to the environment by paper trash and by plastic trash is greater than that caused by any other sort of trash that was studied.
This doesn’t affect the argument. The author compares paper and plastic trash to each other, not to other types of trash.
D
The production of any paper product is more harmful to the environment than is the production of an equal weight or volume of any plastic.
This is another reason paper usage does more damage to the environment than plastic usage. It rules out the possibility that plastic products do more harm to the environment during manufacturing than paper products do.
E
The proportion of plastic trash to paper trash varies from one part of the country to another.
This is accounted for in the study described, so it doesn’t affect the argument. The study examined “representative areas” across the country—differences between those areas do not imply the study was flawed.