Every year many people become ill because of airborne mold spores in

Hey All,

Even though the right answer was eventually arrived at here, there was enough confusion I thought it might be worth outlining. Let's do it.

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.

Conclusion: To avoid mold poisoning, keep plumbing in good condition.
Premises: Specialists check in damp areas of the house/mold is almost always in moist places
Assumption: Plumbing is the only thing that causes moisture.

Now I swear on a stack of bibles I wrote this assumption before looking at the answer choices. Think about it. The argument is airtight, other than this little issue. The conclusion involves plumbing, but that seems pretty specific, doesn't it? What about fixing the roof, so rain water can't get in? Truth is, there are plenty of ways moisture could get into the house.

As for a pattern, this is an eliminate alternate cause question. These are very common on the GMAT CR section, and there's a great thing to know about them: very often, when the question posits that A causes B, the assumption is that B doesn't cause A. It's called a causation/correlation mistake (we see two things happening, for example moisture and mold, and assume that moisture causes mold). Though sometimes the answer will just be any other old cause (like the leaky roof I suggested), very often it's just a reversal (mold might cause moisture). Be on the lookout!

1]Mold itself does not create moisture.
ANSWER: Uh-oh. Think about it. If mold DID create moisture, then it wouldn't be enough to check the plumbing, because the mold could be anywhere. This would explain why it's always found in moist places.

2]Most homeowners know enough about plumbing to determine whether theirs is in good condition.
PROBLEM: This is a tricky one. If the conclusion were, "Homeowners should thus have no problem finding mold on their own," this would be the assumption. But the conclusion is that plumbing needs to be kept in good condition. If you don't know, you'd just have to learn.

3]Mold cannot grow in dry areas.
PROBLEM: We don't need to assume this, because the conclusion is not that all mold will be eradicated if plumbing is checked. It's only that if one wishes to avoid mold, one should keep plumbing in check. Even if mold can grow in dry places, the facts point towards moisture being the most common place to find it, and thus the conclusion would still hold.

4]No varieties of mold are harmless.
PROBLEM: Not the issue. Even if some are harmless, some aren't.

5]Mold spores cannot be filtered from the air.
PROBLEM: This might suggest another way that mold poisoning can be avoided (some type of filtration system), but as the conclusion relates to actually getting rid of the mold where it comes from, this answer choice is out of scope.

Hope that helps!

-t

Conclusion: 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
Premise: specialists look in damp areas of the house, since mold is almost always found in places where there is substantial moisture

As we can see that the premise says that the mold is almost always found in moist areas and then the conclusion asks us to keep plumbing in order to prevent leakage that could serve as breeding ground for mold. Thus, the observation that mold is almost always found in moist areas is led to mean that moist areas lead to molds, not the other way around.

In other words, the observations is like X and Y are always found together. Then, we conclude from this that X leads to Y. In deriving this conclusion, we are assuming that Y does not lead to X and there is no other substance Z, which could lead to both X and Y.

Thus, when we derive that moist areas act as breeding grounds for mold, we are assuming that Mold itself does not create moisture (option A).

Therefore, option A is correct.

Regards,
CJ

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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Caught between A and C

The stem states,"..mold is almost always found in places where there is substantial moisture"

Going with A for this reason.OA pls.

Hey Kiski,

Also, always be aware of really strong statements. C says "Mold cannot grow in dry places". Would we need to assume that mold NEVER grows in dry places? If it happened one out of a million times, would that compromise our argument? Probably not. Always be wary of terms like "cannot", "never", and "always".

-t

if the argument were "..since mold is always found in places where there is substantial moisture.." The C would be correct?!

Actually, no. C would still not be correct. There is no material change in the argument if you remove 'almost'.

The conclusion of the argument is: If you want to avoid mold poisoning, keep all plumbing in good condition.

The point is that moisture could be created by something else - excessive rain, water sprinklers, mold itself - so by just keeping plumbing in good condition, you may not be able to avoid mold.
If mold actually creates moisture, it will always be found in places where there is moisture.

If at all, (C) can be an inference in case you remove 'almost'. The premise gives you that mold is always found in moist places. We must take the premise to be true so we can infer that it cannot grow in dry areas (though, the inference is not perfect. We can say that it can grow in dry areas but it cannot be found there because it is not visible or something...).

Correct Choice is A. Here is my explanation.

Here the author has attributed the dampening of areas to the leakage thru internal plumbing. While doing so he assumes that there are no causes other than internal plumbing responsible for dampening of places. We would look for similar reasoning

A) This choice eliminates the posibility of other cause. Correct.

B) This choice is fantastic and tempting, however passage says homeowner's responsibility is to keep the plumbing in good condition, which he/she can do by calling plumber also and not necessary to personally determine the condition. So incorrect.

C) Wrong. Premise clearly states that molds almost always found in places where there is moisture (We can not refute premises in assumption/weaken questions)

D) irrelevant

E) irrelevant

Hi mun23,

The argument shows a causal relationship between the premises and the conclusion. The conclusion states that one should avoid any moisture at home if one wants to stay away form mold poisoning. The causal relationship is that moisture causes mold. The assumption in this causal argument should support the causal direction of the conclusion. i.e. the assumption must prove that A causes B or moisture causes obesity and nervousness.

The assumptions in a causal arguments are often of two types:

i) Assumptions that support the causality of the argument either by eliminating an alternate cause of the conclusion OR
ii) by demonstrating that the conclusion, it it exists, is in proper direction. In other words A is caused by B and not B has caused A.

Any option which does not tell us anything about the causal link between moisture and mold growth can be safely eliminated.

Lets analyze the answer choices.

(A)Mold itself does not create moisture.

This is in fact ii) from above, i.e. it states that the conclusion exists in proper direction. If mold itself does not cause moisture then it only the moisture that causes mold and the conclusion that "one has to stay away from moisture to avoid mold poisoning" is validated.

(B)Most homeowners know enough about plumbing to determine whether theirs is in good condition.

Not relevant, no link between moisture and mould

(C)Mold cannot grow in dry areas.

Again, irrelevant, the stimulus talks about mold growing in areas with moisture.

(D)No varieties of mold are harmless.

Harmfulness of varieties is again irrelevant.

(E)Mold spores cannot be filtered from the air.

Again irrelevant, whether molds can be filtered will have no effect on our conclusion.

You can try a similar example for practice from the post below.

the-popular-belief-that-a-snake-s-age-can-be-determined-by-147522.html#p1184417

Hope that helps,

Vercules
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Hi ExpertsGlobal5

Doesn't choice A attack the premises? our conclusion is about people controlling plumbing systems to prevent poisoning
do we really care about if mold can pop up in other places?

"Mold itself does not create moisture".

My problem with A is the possibility that mold forms in places in which there is moisture, and only then does mold create additional moisture (/increases the already existing moisture). If mold forms where there is already moisture, answer choice A does not weaken the argument at all.

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. [C]: 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.



My thoughts –

AMP (Avoid Mold Poisoning) -> PGC (Plumbing in Good Condition)

A. Mold cannot grow in dry areas.

Negation: Mold can grow in dry areas

Premise already covers this – “Mold is almost always found in places where there is substantial moisture.”
It means there are other cases when mold could also grow, including in dry areas.
This statement negation does not effect [C].

B. Most homeowners know enough about plumbing to determine whether theirs is in good condition.

Negation: Most homeowners does not know enough about plumbing to determine whether theirs is in good condition.

The homeowners do not have to know themselves, they can just hire professionals to check for them!
This negation will not hurt the [C] – Sneaky! I picked this TWICE myself!

C. Mold itself does not create moisture.

Negation: Mold itself creates moisture.

If this is true that mold create moisture then preventing leakage will not help, so the advice by the [C] is BS and holds no ground as moisture itself is not the root cause, it is merely an effect! This is our answer! Negation works 90% of the time!

D. Varieties of mold are harmless. Irrelevant
E. Mold spores be filtered from the air. Irrelevant

Its actually a very easy question if you think logically and write down the info. correctly, the argument says that -
cause - molds ---> effect - illness
damp areas --> higher chances of molds
then also mentioned that
cause - leakage ----> effect - molds increases by breeding
but what if this cause and effect is not correct what if effect leads to cause? in cause and effect questions always ask -
whether effect leads to cause? or think of alternative causes or situation where NO cause then NO effect.
here our correct answer is A since it mentions that - effect doesn't leads to cause i.e., high volume of molds does not lead to situation where moisture increases.