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.
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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
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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
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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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