Q14 - When soil is plowed

[mchuynh]

Can someone explain to me why is the answer A? Thanks

[ManhattanPrepLSAT1]

Happy to, and thanks for posting your question here!

Based on the stimulus, we know that seeds will germinate if they are briefly exposed to sunlight after spending the winter in prolonged darkness under the soil. However, if the pigweed seeds are tilled at night, they will not be exposed to sunlight and so will not germinate.

(A) must be true. No pigweed plants will grow if the field is plowed at night, whereas some will grow if it is plowed during the day.
(B) is not true. No pigweed plants will grow if the field is not plowed, nor will pigweed plants grow if the field is plowed at night.
(C) is not true. There is no sunlight before sunrise and no sunlight after sunset. So no pigweed plants will grow in either scenario.
(D) is not necessarily true. The stimulus says nothing about the need to redeposited under the soil in order to be germinated.
(E) is unsupported. In fact, these pigweed seeds will probably not germinate if they were not held in prolonged darkness underneath the soil.

Does that answer your question?

[mchuynh]

Yes, thank you!

[dylancox_12]

I guess I misinterpreted their definition of 'briefly' and believed it to mean like over the period of a few weeks (rather than a few hours) of exposure to sunlight. Is there any way I could have known they weren't churned up and then sit there for a few weeks getting sunlight?

[anjelica.grace]

Is there any way I could have known they weren't churned up and then sit there for a few weeks getting sunlight?

Think of it this way. Suppose they were sitting there for a few weeks, they would have had repeated exposure to sunlight. I don't think that qualifies as brief.

[peterbobolis]

aren't they still under darkness when plowed at night, only to get their brief germinating sunlight at sunrise?

[ManhattanPrepLSAT1]

I guess I misinterpreted their definition of 'briefly' and believed it to mean like over the period of a few weeks (rather than a few hours) of exposure to sunlight. Is there any way I could have known they weren't churned up and then sit there for a few weeks getting sunlight?

Notice that the stimulus tells us that the seeds are redeposited back below the surface when the soil is plowed. So we do know that the seeds are not sitting on the surface for weeks, days, or even hours!

aren't they still under darkness when plowed at night, only to get their brief germinating sunlight at sunrise?

Not exactly. If the soil is plowed under darkness (and that includes all times between sunset and sunrise), then the seeds will not be exposed to any sunlight. They are redeposited back under the surface when the soil is plowed and so would not see any light at all.

[dean.won]

Does "D" confuse necessary with sufficient??

[michaelwcarper]

I'm having difficulty between A and B.

It seems to me that this stimulus an makes assumption about the time span required for plowing. It says that "when the soil is plowed...[the seeds] are redeposited just under the surface" and that this is "brief exposure to sunlight."

But how do we know that the "depositing" happens immediately? What if the seeds just sat on the surface for, say, an hour or two or three? We don't know how much time elapses during plowing. You might say that this is not
"brief" exposure but we don't have a basis for saying what "brief" is.

There's also the possibility that they could sit on the surface for 3 hours, but only in the last 5 minutes be exposed to sunlight. i.e., if they plow at 3 AM in the morning. This would be "brief."

[christine.defenbaugh]

Really interesting question, michaelwcarper!

Let's knock something big out of the way right here at the top: on an inference question, you MUST accept all the information in the stimulus as true!!! In fact, it says so right in the question stem: "The statements above, if true, ...."

So, even if the author were making 'an assumption' about how long plowing takes, we would have to take that assumption as true also. The author tells us that the exposure is brief - our opinion on whether plowing exposure is 'brief' or not doesn't matter. We have to take that statement as true!!

[It helps, but is not necessary, to have a basic understanding of what the word "plow" means. The definition is strongly suggested in the stimulus. It means, simply, to churn up the soil. It's not like someone is running around in the field digging up the pigweed seeds, laying them out on the ground, waiting awhile, then returning them to just under the surface. Someone, or a machine, just churns up the soil like a moving blender. ]

So we have to take it as gospel that when we plow, pigweed seeds get "briefly" exposed to whatever the sky is doing at that moment, then redeposited under the surface.

We now know a few fundamental things:

1) SPRING PLOWING = buried pigweed seeds are churned up, briefly exposed to the surface, then redeposited under the surface.
2) Long-dark, followed by sunlight-exposure (even brief) triggers germination.
3) Without long-dark, then sunlight-exposure, seeds won't germinate.

So, if we plow at night, those pigweed seeds will only be briefly exposed to the night sky, and therefore won't get any sunlight at all.

But, let's play devil's advocate just for a moment - let's say you're right that night plowing would actually somehow give a brief exposure to sunlight. (B) says that night plowing is BETTER than "if it is plowed at all". How would we support that notion? Even if night-plowing could give brief sunlight exposure, wouldn't night-plowing and 'plowing at all' be equal?

If we argue that night-plowing is JUST AS GOOD as day-plowing in terms of sunlight exposure, then neither (A) nor (B) would be supported.

Also, if the author is saying that spring plowing gives a brief exposure to sunlight, but only when the plowing happens at exactly 3AM (because plowing takes 3 hours to complete, and the sun rises at 5:55am, so there's five minutes of sunlight, etc), then the author would have needed to clarify that that's the only time that plowing works the way he's describing. Instead, he made a general statement: "When soil is plowed in the spring....here's what happens". Don't add in crazy specific limitations that aren't present in the stimulus.

And remember: this is an inference question, and you must accept the statements as truth. Right now, you're trying to argue with the information you've been given in the stimulus, and that won't get you anywhere!

Please let me know if this helps clear up a few things!

[michaelwcarper]

But, let's play devil's advocate just for a moment - let's say you're right that night plowing would actually somehow give a brief exposure to sunlight. (B) says that night plowing is BETTER than "if it is plowed at all". How would we support that notion? Even if night-plowing could give brief sunlight exposure, wouldn't night-plowing and 'plowing at all' be equal?

If we argue that night-plowing is JUST AS GOOD as day-plowing in terms of sunlight exposure, then neither (A) nor (B) would be supported.

Is that a typo? Answer choice B says "fewer pigweed plants will grow in the field if it is not plowed at all than if it is plowed only at night."

We're comparing no plowing to plowing at night. Without any kind of plowing, there can definitely be no exposure to sunlight, so we can be sure that the "no plowing" option will produce 0 germinated seeds.

So the night plowing option would only need to germinate a single seed to make choice B correct.

I can see how B is less supported than A. My point is merely that the language of the stimulus is not specific enough about the timing of plowing to rule out B alltogether.

[christine.defenbaugh]

Is that a typo? Answer choice B says "fewer pigweed plants will grow in the field if it is not plowed at all than if it is plowed only at night."

We're comparing no plowing to plowing at night. Without any kind of plowing, there can definitely be no exposure to sunlight, so we can be sure that the "no plowing" option will produce 0 germinated seeds.

So the night plowing option would only need to germinate a single seed to make choice B correct.

I can see how B is less supported than A. My point is merely that the language of the stimulus is not specific enough about the timing of plowing to rule out B alltogether.

It's entirely possible my copy has a typo! I'll look into that!

However, that only addresses my devil's advocate argument. You still haven't addressed the rest of my post, or the fact that the stimulus fairly clearly indicates that plowing results in the seeds getting a 'brief' exposure to the sky, *and* that we must accept everything in the stimulus as true.

You're also still fighting against the task you've been given: this is a 'most strongly supported' inference type. If you can see how (A) is more supported than (B), then that means it is the right answer - the question is asking for the answer that is more supported!

But there's a procedural issue even more important than that: it is not necessary that we be able to prove each wrong answer is false - merely that it doesn't have solid and direct support. (As an example, (D) could potentially be a true statement, as nothing in the stimulus rules it out, but there's also nothing in the stimulus that supports it as true either.) To support (B) from the stimulus, even a little, we'd need clear support that night-plowing is likely to give the seeds sunlight-exposure.

If we're plowing at night, with a mere brief exposure to the sky, then we would have to tie ourselves in knots to create a specific scenario where these seeds get exposure to sunlight as a result of the plowing. We don't have any support in the stimulus for making those specific and somewhat peculiar scenarios.

Once we accept that our task is to find the answer that actually has clear support, and also accept that the stimulus is giving us a definition of plowing that includes only a brief exposure of the seeds to the sky, the support for (B) withers away.

Make sense?

[thwolfe]

I couldn't decide between A or B, and I mistakenly chose B.

My reasoning:

There is some natural light at night time, and all natural light is sunlight. The moon, after all, only shines because it reflects light from the sun. Since the receptors are "highly sensitive," there's no indication that more sunlight makes more germination: the most minuscule amount of sunlight may be all that is needed, and that may be achieved from the minuscule amount of sunlight during the night. Therefore A needn't be true, because they could germinate equally at night and day.

But, as the stimulus says, they certainly can't germinate if left underground. Therefore B is correct.

Evidently I've overthought it, but I still think that, technically, this reasoning is more supported.

[drothhello]

Here's the most confusing thing for me:

It says that the seeds are churned up and redeposited just under the surface.

First off, though I have been on a farm a couple of times I don't know shit about plowing. I'm thinking, "Ok, they're redeposited back under the surface, but when friend?! When are they redeposited?"

Maybe the seeds are on the surface for a couple of minutes, a couple of hours, days, etc. It just says "briefly". Due to this ambiguity, answer B is lookin pretty good.

You have to assume that this redepositing process happens immediately. Why couldn't they just say that word, "immediately?" Again I don't know shit about plowing.

[bswise2]

Like many who have posted above, I am stuck between A and B. Regardless of all the well reasoned defenses for A that I have read so far, I still see B as the most logical choice.

A states that "Fewer pigweed plants will grow in the field if it is plowed only at night than if it is plowed during the day."

The facts that we are given do not specify how long the seeds remain on the surface before they are redeposited under the surface. I figured that, because the fact pattern did not specify, that I should not make any unsupported assumptions. It could be hours or days (in which case, it would not matter whether they were plowed at night or during the day because the seeds will be exposed to sunlight eventually before they are redeposited) or minutes. Choosing answer A requires that you make the arbitrary assumption that, if the soil was plowed at night, the seeds will be redeposited before the sun can trigger their germination.

Futhermore, I think thwolfe makes a great point. Choosing A also requires us to make the assumption that sunlight received through the moon is not enough to trigger the germination, regardless of the fact that the seeds are "highly sensitive" to sunlight. The facts never specify that there needs to be a specific length of time/type of exposure to sunlight. Following logically from what we are given, the moon could very well suffice.

B states that "Fewer pigweed plants will grow in the field if it is not plowed at all than if it is plowed only at night."

To me, this conclusion is inevitable. How many pigweed plants will grow if the field is not plowed? None. How many pigweed plants will grow if the field is plowed at night? Considering the seeds which have been brought to the surface are exposed to more sunlight than they were before (the moon, dawn, sunrise--again, this requires the facts to clarify how long the seeds are on the surface before they are redeposited. Any assumption I am making here is meant to remain as broad and inclusive as possible), more than none. There may not be many seeds that germinate, but even 1 or 2 would be enough to conclusively say that plowing at night results in more germinated seeds than not plowing at all.