Juaz wrote:
Every year many people become ill because of airborne mold spores in their homes. After someone becomes ill, specialists are often hired to eradicate the mold. These specialists look in damp areas of the house, since mold is almost always found in places where there is substantial moisture. If one wishes to avoid mold poisoning, then, one should make sure to keep all internal plumbing in good condition to prevent leakage that could serve as a breeding ground for mold.
Which of the following is an assumption on which the argument depends?
A. Mold cannot grow in dry areas.
B. Most homeowners know enough about plumbing to determine whether theirs is in good condition.
C. Mold itself does not create moisture.
D. No varieties of mold are harmless.
E. Mold spores cannot be filtered from the air.
OFFICIAL EXPLANATION
The basic structure of this argument is fact that “mold is almost always found in places where there is substantial moisture,” so therefore, to avoid mold and the resultant mold poisoning, then people should take steps to prevent wet areas. This argument assumes that wet areas occur first, causing mold to grow. Conversely, this assumption requires that the mold growth itself does not occur first, creating wet areas as a result.
(A) CORRECT. The argument depends on the assumption that the reason mold and wetness are observed together is that wet areas cause mold growth. If the reverse causation (mold causes wetness) were true, then keeping all plumbing in good condition to prevent leakage would do little to prevent the growth of old. This choice eliminates the alternate causation.
(B) If most homeowners know enough about plumbing to determine whether theirs is in good condition, then the recommendation made in this argument would be more useful. However, this is not an assumption on which the argument depends.
(C) Even if mold could grow in dry areas, the fact that mold is almost always found in wet areas is still valid. This is the fact upon which the argument is based, so the argument does not depend on the unnecessarily absolute assertion that mold cannot grow in dry areas.
(D) Even if some varieties of mold are harmless, the conclusion of this argument, that “one should make sure to keep all internal plumbing in good condition to prevent leakage” and minimize mold growth, could still be valid. Therefore, this argument does not depend on the unnecessarily absolute assertion that no varieties of mold are harmless.
(E) Whether mold spores can be filtered from the air may be relevant to a conclusion about the health effects of mold in the home, but it is not directly relevant to this conclusion, that “one should make sure to keep all internal plumbing in good condition to prevent leakage” and minimize mold growth.
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