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This is a strengthen question, according to our question stem. That say, you need to find an answer choice hat reinforce the conclusion. And confirm what our argument are saying.

This is our conclusion in the argument above



We must find the answers that make this statement stronger. You can follow mainly 2 strategies: or POE or pre-thinking reading the argument itself.

A- The levels of the compounds typically used in boat paints today are lower than they were in boat paints manufactured a decade ago.

A comparison between two eras f production is out of scope

B- In high concentrations, the compounds are toxic to many types of marine animals.

This is a generalization about most of the marine animals

C- The compounds break down into harmless substances after a few months of exposure to water or air.

This is the right answer: the water in which the compound is present, break down after a certain amount of time. As such, the dolphins are not in contact with the substance. Hence, they are not affected

D- High tissue levels of the compounds have recently been found in some marine animals, but there is no record of any of those animals dying in unusually large numbers recently.

Again: a comparison and its concentration in different animals it is not in our argument

E- The compounds do not leach out of the boat paint if the paint is applied exactly in accordance with the manufacturer’s directions.

The process through wich the paint is well fixed to the boats by manufacturers are not in our argument

Do not hesitate to ask if something is unclear

This is a tough question. Here is my thinking.

The argument says that by constantly exposing the boat paint is reducing dolphins resistance to infections and they eventually die. If the compounds were to break down into harmless substances after a few months of exposure to water or air (Answer Choice C) and exposure to new boat paint is stopped through banning boat paint (the conclusion), the dolphins will increase their resistance to infections, and deaths will eventually decline.

Recently an unusually high number of dolphins have been found dead of infectious diseases, and most of these had abnormally high tissue concentrations of certain compounds that, even in low concentrations, reduce dolphins’ resistance to infection. The only source of these compounds in the dolphins’ environment is boat paint. Therefore, since dolphins rid their bodies of the compounds rapidly once exposure ceases, their mortality rate should decline rapidly if such boat paints are banned.

Which of the following, if true, most strengthens the argument?

A) The levels of the compounds typically used in boat paints today are lower than they were in boat paints manufactured a decade ago.
B) In high concentrations, the compounds are toxic to many types of marine animals.
C) The compounds break down into harmless substances after a few months of exposure to water or air.
D) High tissue levels of the compounds have recently been found in some marine animals, but there is no record of any of those animals dying in unusually large numbers recently.
E) The compounds do not leach out of the boat paint if the paint is applied exactly in accordance with the manufacturer’s directions.

Another way to think of a strengthen question is: which answer, if I were to weaken it, would thus weaken the conclusion?

Choice C is the correct answer because the only way banning such boat paint will work is if the boat paint already floating around were to become less toxic to the dolphins over time. This is what's known as a "Cause and Effect" assumption.

The 5 main types of assumptions (CCRIQ*)

C = Cause and Effect (or Correlation and Causation)
C = Comparison and Analogy
R = Representativeness
I = Implementation
Q = Questionable Evidence / Quantitative Methods

*(from "Ace the GMAT" by Brandon Royal)

Incorrect answer analysis:

Keep in mind that any strengthen/weaken answer choice can be evaluated by how directly relevant it is to the conclusion itself.

A) Who cares about 10 years ago? The conclusion is about the future.
B) The conclusion pertains to dolphins, not other marine mammals.
D) Again "marine animals" are not the same as dolphins.
E) The problem already exists, so clearly this is not relevant. Similar to Choice A.
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Hello Everyone,

Correct me if I am wrong that is, if the compound breaks down into harmless substances then their is no need to ban it as specified in the last sentence. If we think like that it will only weaken the argument not strengthen it....

The ban is important because in few years the boat paint of THOSE existed BEFORE the ban depletes in few years. If this happens BUT we do not ban the boats and their paints, we will end up in a spiral endless.

I.E: we have 10 boats and from now they are banned. In one year the compound is dissolved and dolphins gain numbers. BUT if the boats are not banned even if the compound depletes we will have alway it because new boats will introduce it once gain because NOT banned.

Hope this helps

Explanation

All answers are wrong but C. E is a trap answer

Because we do not care about that the paint does not leak, we care that the mammals have no contact at all.

C is the best.

Why B is not the answer? since it supports the cause of banning of boat paint more strongly as as other aquatic mammals and species are also getting affevted which is strengthening the argument.

B is wrong because we already know that is toxic. B nothing adds to the question.

C instead makes it stronger. IF the ban will take place, the compound soon will fade. This suggests us that - the other way around - the banned will last, the dolphins will die at an increasing rate.

Hope this helps

I think this is a confusing and tricky one. I have gone through the explanations and no matter how much I would have thought about it, I would have still chosen B. The argument is that banning boat pain will reduce Dolphin death. It is very hard to understand how option C supports that argument.

B is just giving reason, plus its out of scope as it is mentioning other species and we are not concerned about them.
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The argument is that banning boat paint will decrease mortality rate. In option c it is there in water for some amount of time. Only after some time it gets harmless? so during that short interval it can still be harmful. And Why not option E? Carcass

Recently an unusually high number of dolphins have been found dead of infectious diseases, and most of these had abnormally high tissue concentrations of certain compounds that, even in low concentrations, reduce dolphins' resistance to infection. The only source of these compounds in the dolphins' environment is boat paint.

Ok. Many dolphins died for a certain venomous compound that even in low concentration in the body's tissues provoke the death of these mammals


Therefore, since dolphins rid their bodies of the compounds rapidly once exposure ceases, their mortality rate should decline rapidly if such boat paints are banned.

The dolphins have the capacity to clean-up their own body, so if we stop to use or introduce the compound in their environment, the deaths should be stopped


A) The levels of the compounds typically used in boat paints today are lower than they were in boat paints manufactured a decade ago.

An unuseful comparison between types of paints in different decades. Does not tell anything


B) In high concentrations, the compounds are toxic to many types of marine animals.

This compound is also very dangerous to other animals. Does not tell anything how to save the dolphins


C) The compounds break down into harmless substances after a few months of exposure to water or air.

This is correct. If the dolphins do not have exposure to the compound. It will deceade very fast

D) High tissue levels of the compounds have recently been found in some marine animals, but there is no record of any of those animals dying in unusually large numbers recently.

Other animals. Does not say anything of useful. It is just a waste of time this option

E) The compounds do not leach out of the boat paint if the paint is applied exactly in accordance with the manufacturer's directions.

Tricky but we do not know if the paint is applied correctly. The manufacture says the directions. But we do not know if these directions then, in reality, are effective.

Moreover, think the boat has an accident and breaks apart into the ocean. We do have a leach right ??

The best way to reinforce the argument is that the dolphins will NOT have any contact

Hope this helps

Regards

Small query

1. option E like we do not know whether they followed manufacturer's instruction or not. So there is a possibility that if not followed could be danger for dolphins. Is the interpretation correct?

2. Option C:- It says after a few months of exposure to water...But here the substance remains in water for few months before it becomes harmless.

Carcass

E is wrong, regardless, because we do not have enough information

C is correct because it says C) The compounds break down into harmless substances after a few months of exposure to water or air.

if the dolphins will not have any more contact with the boats, they will be safe. The compound will fade away

And this is consistent with the argument

Therefore, since dolphins rid their bodies of the compounds rapidly once exposure ceases, their mortality rate should decline rapidly if such boat paints are banned.

We ban the boats >>>> we do know that the compound will fade away. And this is confirmed by C

Regards

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