#14 - When soil is plowed in the spring, pigweed seeds that

[Luke Haqq]

Hi destiny.ram!

To your question of how you can avoid making the mistake of eliminating the correct answer choice, I can suggest a couple things.

First, it's important to read the stimulus carefully; if one word like "prolonged" strikes use as an important one and decisive for eliminating answer choices, then I would make sure to go back to the stimulus, find that word, and confirm how it is being used. In this question, the word arises specifically in reference to "prolonged darkness." In terms of how to avoid mistakes, this is simply just a reminder about the importance of going back to the text and confirming specific citations (much like one would do for questions in reading comprehension that ask about the use of a specific term and provide a line reference for where it occurs).

Second, it's also important to be in a habit of diagram conditional reasoning when you encounter it. Related to this, the next step of making inferences based off of that conditional reasoning can also be critical to honing in on the right answer, rather than accidentally eliminating it. Here, we are told, "Without the prolonged darkness, followed by exposure to sunlight, the seeds do not germinate." To diagram this, note that it's helpful to apply PowerScore's method for conditional reasoning involving words like "unless," "without," and similar words. Whatever variables are modified by that word become the sufficient condition (left of the arrow) and the remainder is negated and is placed as the necessary condition (right of the arrow). This would produce:

seeds germinate prolonged darkness AND subsequent sunlight exposure

In other words, if seeds germinate, then this means there was both prolonged darkness and sunlight exposure. In encouraging you to diagram conditional reasoning as well as inferences that can be made about it, taking the contrapositive is a great place to start. For the above statement, that would be:

prolonged darkness OR subsequent sunlight exposure seeds germinate

In other words, if either prolonged darkness or subsequent sunlight exposure don't occur, then seeds won't germinate.

Having the above diagramming could help you arrive at answer choice (A) as the correct one. That answer choice reads, "Fewer pigweed plants will grow in the field if it is plowed only at night than if it is plowed during the day." Though the word "if" is tucked into the sentence rather than at the beginning, this is really just if-then conditional reasoning, which can be diagrammed as:

plowing only at night fewer pigweed plants grow

Based on the conditional reasoning from the stimulus that we diagrammed, we know that this must be true. There would be fewer pigweed plants growing because there would be no subsequent sunlight exposure. The contrapositive shows why this is the case. One does not even need to get to the "prolonged darkeness" aspect part because we're already told from the question stem is asking about "a field [that] will be plowed in the spring and in which pigweed seeds have been buried in the soil all winter." The prolonged darkness is therefore a given, but we're missing the subsequent sunlight exposure. Without both of those, seeds won't germinate.

[PresidentLSAT]

Hi Powerwcore,

Are we to assume that when plowing is done during the day, there is some exposure to prolonged darkness?

[Robert Carroll]

President,

No need to assume! The question gives you the info that the seeds have been buried all winter, which is the prolonged darkness you're looking for.

Robert Carroll

[Hyunuk Park]

A killer, trick and a strange question. (I get the answer) A frustrating question.

- The first sentence, indicates "redeposition" as a process, but we have no grounds to confirm that redeposition is necessary. HAHA
- A is the answer; although it’s reasonable to think plowing at night would leave the seeds to see the sun on the days following, “if only plowed at night than it is plowed during the day” confirms that it is not exposed to sunlight.

[Jeff Wren]

Hi Hyunuk,

You're right that redepositing is not required to germinate. Only the final sentence of the stimulus addresses what is necessary for the seeds to germinate, prolonged darkness followed by exposure to sunlight.

This is a Most Strongly Supported Question, which is just a variation of a Must Be True question with a lower degree of certainty that the answer needs.

It's very important when doing these questions to read very carefully and to just "stick to the facts."

The stimulus states that when the soil is plowed, the seeds "are churned up to the surface and then redeposited just under the surface." (my emphasis). The stimulus then describes how this "brief exposure to sunlight" stimulates the receptors to germinate. The brief exposure to sunlight refers to the brief time (perhaps seconds) that the seeds are churned up before being redeposited under the surface.

Based on what is stated in the stimulus, there is no reason to think that the seeds would be exposed to the sun if they were plowed at night because those seeds would now be under the surface by that point. While there may be some (as in a few) seeds that remain on the surface after plowing, the stimulus states that in general, the seeds are redeposited under the surface during the plowing. Since the exposure to sunlight is necessary for the seeds to germinate, we can be confident that there would be fewer plants if plowed only at night as stated in Answer A.

[99bengardner@gmail.com]

I have an objection to this question. I understand it, and why my original response (B) is wrong under LSAT logic, but still take issue with it.

The prompt is "The statements above, if true, most strongly support which one of the following statements about a field that will be plowed in the spring and in which pigweed seeds have been buried in the soil all winter?" Answer (B) is "Fewer pigweed plants will grow in the field if it is not plowed at all than if it is plowed only at night."

This, (B), is not a statement about a field that will be plowed in the spring.

My second objection is that it is common sense knowledge that moonlight is refracted sunlight, and that some nights involve moonlight. This, combined with the seeds' "receptors, which have become highly sensitive to sunlight" makes (A)'s "more grow in day as opposed to night" not a necessarily true statement as e.g. the receptors could be so sensitive that moonlight is equally sufficient stimulation as direct sunlight. Answer (A) is "Fewer [...] will" as opposed to "Fewer [...] might", which requires that there be no possible situation in which equal numbers grow such as the "so sensitive" example above. Thus the only reasonable answer is (B).

Could someone suggest a rule of thumb for escaping either of these two objections in other problems? This is the first question in about 200 I've taken issue with

[Jeff Wren]

Hi bengardner,

Answer B (as well as Answers A and C) provides a comparison between two different situations. For Answer B, the comparison is between a field plowed only at night and a field that is not plowed at all. While you are correct that a field that is not plowed at all does not match the criteria stated in the question stem of "a field that will be plowed in the spring," a field plowed only at night does match the criteria, and only one of the comparisons needs to be a "a field that will be plowed in the spring." The fact that the comparison is being made between something that is not also "a field that will be plowed in the spring" is not actually a problem.

For example, imagine Answer B had said "A field plowed only at night will not result in significantly more plants than a field that is not plowed at all. This would be a statement about a field plowed in the spring that is supported by the information in the stimulus. Since we are told in the stimulus that "exposure to sunlight" is required for the plants to germinate, a field plowed only at night would not result in many plants germinating (since the seeds are redeposited under the surface during the plowing.)

While it may be common knowledge that moonlight is refracted sunlight, the two terms are not synonymous in general use and you should definitely not assume that moonlight would be equivalent/sufficient to cause the seeds to germinate. Perhaps the stimulus could have been more clear by using the phrase "direct sunlight," but we work with what the test makers give us, and the questions aren't always 100% perfectly written.

As for when to avoid nitpicking, it's important to read very carefully and be critical/sceptical of answer choices. However, this skill can sometimes backfire when students start talking themselves out of the best (correct) answer. Especially for Most Strongly Supported questions, the answer should be generally supported by the information in the stimulus, but need not 100% follow directly like a true Must Be True question. In these questions, you need to reduce your level of certainty and comparing/contrasting the answers becomes even more important.

Lastly, you should try to focus on what the question is really about, what particular skill this question is testing, what part of the stimulus is the most important, etc.. Here, the key idea appears in the final sentence of the stimulus, the conditional statement that provides two separate necessary conditions to germinating. This idea, combined with understanding the specific details of how the plowing process works (i.e. the brief exposure to sunlight before being redeposited back into darkness under that surface) provides the support for Answer A.