LR Question 24 Explanation, by LSATHacks
QUESTION TEXT: Many homeowners regularly add commercial fertilizers to …
QUESTION TYPE: Must Be True
FACTS:
- Most commercial fertilizers just have macronutrients.
- Plants also need micronutrients.
- Raking grass removes micronutrients.
ANALYSIS: You can combine all three statements to say:
“If grass is raked away, then commercial fertilizers alone won’t be enough to keep plants healthy”
That’s all we know. All the wrong answers mix up sufficient and necessary.
___________
- The stimulus said that the most widely available fertilizers only have macronutrients. But there could be some less common fertilizers that include micronutrients as well.
- This answer reverses sufficient and necessary. The stimulus says that commercial fertilizers are a sufficient condition for having macronutrients. But other things could also have macronutrients. Heck, you can buy potassium pills.
- CORRECT. This combines all three facts. If you rake away grass, then the soil will be missing micronutrients. Yet most commercial fertilizers don’t contain micronutrients.
- This is very tempting. Its true that commercial fertilizer + grass clippings seem like a sufficient condition for soil health. But this answer says that they are a necessary condition. We don’t know that. Maybe soil doesn’t need commercial fertilizers – forests don’t need fertilizer.
- If you rake up grass clippings, your soil will lack micronutrients, true. But there might be ways to restore micronutrients.
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The question stem says “to remain healthy in the long term, soil for lawns REQUIRES the presence of macronutrients….and micronutrients.” Wouldn’t this put the presence of both macro and micro nutrients as the necessary condition for the sufficient condition of the soil remaining healthy in the long term? Your analysis, and explanation for why answer D is wrong, seems to contradict this and say the opposite, so I am confused as to how we should discern/conclude the conditional reasoning for this problem from the stimulus? Moreover, there was a slight difference in the terminologies used in the stimulus, from “maintaining a healthy balance of nutrients in soil” (which the problem says fertilizers with macronutrients are added in order to do so) to “remaining healthy in the long term” (which the problem expands and says you need micronutrients too for that to happen). Are we supposed to infer both are the same and mean the same thing? Because that different terminology is also noted in answer choices C and D. Thank you in advance for clarifying!!
(1) The stimulus says “for LAWNS to remain healthy in the long term” they require certain macronutrients and micronutrients; the answer choice says “for SOIL to remain healthy in the long term”. That’s why the explanation brings up the example of soil in forests–maybe there are other kinds of soil that don’t require these nutrients in order to thrive. Also, the answer choice says that “commercial fertilizers” in particular are required, whereas the stimulus just says that macronutrients (which happen to be found in commercial fertilizers) are required.
(2) The final sentence of the stimulus refers to long-term health, so that does match the answer choice.