Because dried peat moss, which is derived from sphagnum moss, contains no chemical additives and is a renewable resou...

Nikko on July 7, 2015


Please explain why the correct answer is what it is. Thank you

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Naz on July 8, 2015

Conclusion: gardeners are mistaken in their belief that the use of peat moss in large quantities is environmentally sound.

Why? The millions of acres of sphagnum moss--which peat moss is derived from--contributes to more of the world's oxygen to the atmosphere than do all of the world's rain forests combined. Thus, the garden soil industry, by using peat moss in such large quantities, is depleting these areas much faster than they can renew themselves.

Alright, so what's the issue here?

Well, we are concluding that the use of large quantities of peat moss is not environmentally sound because it is depleting areas in the world that contribute large quantities of oxygen to the atmosphere.

Remember, we cannot bring outside knowledge into the LSAT. Our world, during the LSAT, begins and ends in the boundaries of each question. Thus, even though it makes sense that depleting such a region that contributes so much to the world's oxygen in the atmosphere is not environmentally sound, for the purposes of the question, we have not been given that information. So, it would strengthen our argument if we were explicitly told that if a practice significantly reduces the amount of oxygen entering the atmosphere, which the passage states the use of peat moss in such large quantities does, then that practice is not environmentally sound, i.e. answer choice (B).

Thus, as you can see, answer choice (B) helps strengthen the conclusion that these gardeners are not correct in thinking that their using of peat moss is environmentally sound.

Hope that clears things up! Please let us know if you have any other questions.

DavidW on March 6, 2020

Hi! Could you please give a little info on why D is incorrect? Thank you!

shunhe on March 28, 2020

Hi @DavidW,

Thanks for the question! (D) faces two major problems. One problem is that the sufficient condition has to do with weighing the environmental benefits of a practice against the environmental costs. However, note in the passage that no such weighing occurs. We’re told that there are environmental costs as a result of using spaghnum moss, but we aren’t told about the magnitude of that environmental cost, nor are we told about any environmental benefits and the magnitude of those environmental benefits. Another problem with (D) is that if we look at the structure of the logic it tells us that if X, then the practice can be considered sound. However, we can’t use (D) to conclude that a practice is environmentally unsound. And the conclusion made in the passage is that the practice is environmentally unsound. For these two reasons, (D) is not the correct answer.

Hope this helps! Feel free to ask any other questions that you might have.