When soil is plowed in the spring, pigweed seeds that have been buried

Question

When soil is plowed in the spring, pigweed seeds that have been buried in the soil all winter are churned up to the surface and redeposited just under the surface. The brief exposure of the seeds to sunlight stimulates receptors. Which have become highly sensitive to sunlight during the months the seeds were buried in the soil, and the stimulated receptors trigger germination. Without the prolonged darkness, followed by exposure to sunlight, the seeds do not germinate.

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?

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

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

(C) Fewer pigweed plants will grow in the field if it is plowed just before sunrise than if it is plowed just after sunset.

(D) The pigweed seeds that are churned up to the surface of the soil during the plowing will not germinate unless they are redeposited under the surface of the soil.

(E) All of the pigweed seeds that are already on the surface of the soil before the field is plowed will germinate.

craky · Answer

1:24, but only because I picked A just after reading first two answers. Not quite safe strategy, but worked this time.

gtr022001 · Answer

ya i was thinking of swapping A and E to force everyone to read each answer, o well, next time.

vineet474 · Answer

My explaination goes like this. Please correct me as I got OA wrong.

(E) All of the pigweed seeds that are already on the surface of the soil before the field is plowed will germinate.
Extreme language and irrelavent --eliminate

(D) The pigweed seeds that are churned up to the surface of the soil during the plowing will not germinate unless they are redeposited under the surface of the soil.
This one actually makes sense to me and I marked this one as correct. Reason: in the stimulus, focus on the line "The brief exposure of the seeds to sunlight stimulates receptors". Which means that the seeds have to be redeposited under the soil to make germination work. D perfectly captures this point.

(C) Fewer pigweed plants will grow in the field if it is plowed just before sunrise than if it is plowed just after sunset.
Eliminate : Time is irrelavent here because at whatever time seeds are ploughed, they will eventually get the sunlight as and when the sun rise.
I believe that the point here is that whether they are redeposited after a BRIEF EXPOSURE to sunlight or not.

(B) Fewer pigweed plants will grow in the field if it is not plowed at all than if it is plowed only at night.
Eliminate: If seeds are not plowed AT ALL, how will they be able to capture sunlight? Hence, receptors will not be stimulated and germination will not happen

(A) Fewer pigweed plants will grow in the field if it is plowed only at night than if it is plowed during the day.
Eliminate : Time is irrelavent here. Same reasoning as C. :roll:

but this one is correct.

Help me out guys.

Thanks
-V

but this one is correct. Help me out guys. Thanks -V

gtr022001 · Answer

yah after re-reading, choice (D) does sound like a contender...however, read this part very carefully --
"pigweed seeds that have been buried in the soil  all winter  are churned up to the surface and redeposited just under the surface"

see if you catch the point

vinzycoolfire · Answer

IMO B.
germination, to the best of my knowledge doesn't happen overnight and there is no evidence in the passage that it does. so plowing at night or day does not make a difference. so A and C are out.
E is completely irrelevant.
D. there is no evidence that direct sunlight actually harms the germination process.
Take B. it says if field is not plowed it will have less germination than when it is plowed at night. now take the "at night" part out. the sentence says the field will have germination if it is plowed and no germination if it is not plowed. perfectly right. there is evidence. hence B

vineet474 · Answer

Thanks for showing your interest bro, but I am still not able to catch the point.

How can "ALL WINTER" make a difference here ? Please explain. -V

maddy2u · Answer

@Vineet : lol .. you are right. that makes no sense..

If you go through the conclusion of the stimulus carefully, you will immediately find the reason why D is the incorrect answer choice.

Lets go through that once.
 "Without the prolonged darkness, followed by exposure to sunlight, the seeds do not germinate."

The Conclusion says that without prolonged darkness followed by  exposure to sunlight  (It is not necessarily Brief), seeds do not germinate. That is not what the conclusion signifies

Choice D incorrectly states that only if there is a brief exposure to sunlight, seeds will be able to germinate. 
(D) The pigweed seeds that are churned up to the surface of the soil during the plowing will not germinate unless they are redeposited under the surface of the soil.

gtr022001 · Answer

ha ha so harsh for trying to help, what i got from the passage was, b/c the seeds were buried 'all winter', the prolonged darkness allowed the seed to germinate

choice (d) states that the pigweed will not germinate unless they are re-deposited under the surface, which is true, but, what it is really missing is the prolonged darkness that is required...

i guess its not the 'all winter' its the prolonged darkness that is required as Maddy pointed out, my bad.

vineet474 · Answer

I got your point when you say that "it is not ONLY brief exposure to sunlight that will cause the seeds to germinate" and choice D) is indeed wrong.
However, option A) (the correct answer) is also not helping the cause. Here goes..

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

So,if the seeds are burried "all winter" ( prolonged DARKNESS), and then plowed(whether day or night) , they will eventually get the sun light they require to germinate. How can this  time factor  can make a difference here and that fewer pigweed plants will grow in the field if it is plowed only at night than if it is plowed during the day?

Thanks,
-V

gtr022001 · Answer

sorry vineet474, but i think i led you astray with my previous posts, so looking at this again, between (A) and (D)

(A) Fewer pigweed plants will grow in the field if it is plowed only at night than if it is plowed during the day.
 
this is true, b/c the greater chance of germinating would be when there is sunlight (brief exposure stimulates receptors)

(D) The pigweed seeds that are churned up to the surface of the soil during the plowing will not germinate unless they are redeposited under the surface of the so
 
not true, b/c depending on when the plowing takes place, day or night, if its in the day, then yes it will germinate (if there is sunlight). if it is at night, then no, it will not germinate

i think this will be my last crack at this question...

D4kshGargas · Answer

(A)
It’s like when we exposed the seeds for let’s say 5 mins, those 5 minutes of exposure were enough to trigger germination, even though the seeds were then again buried under the surface.

Initially, I thought burring them just under the surface might expose them to sunlight 
But I guess that’s the wrong way!

Thoughts?

Posted from my mobile device

MBAB123 · Answer

Hey, I think "churned up to the surface" is when the point when exposure to sunlight is happening. So yeah, your first point is correct. But, I totally get your initial thought as well and where it's coming from.

rmahe11 · Answer

GMATNinja , if the seed are plowed after the sunset , they will be in prolonged darkness and hence will also get exposure to sunlight which will help in germination right ? So , how come C is not correct

glagad · Answer

I will try to answer this -

the prolonged exposure to darkness is referred to as when the seeds have been buried under the soil already.

exposure to sunlight happens after plowing

This choice translated to - Number of seeds germinating (if plowing done before sunrise) < Number of seeds germinating (if plowing done after sunset)

The reality is just the opposite as there is more sunlight exposure in the former case thus increasing the chances of stimulation

GMATNinja · Answer

Choice (C) compares two scenarios:

1. Plow the field just before sunrise.

2. Plow the field just after sunset.

The prompt tells us that the pigweed seeds have been buried in the soil all winter, so we already know that the "prolonged darkness" requirement has been satisfied in  either  of those two scenarios.

Without being given any other information, we have to assume that there's just as much sunlight  just  before  sunrise  as there is  just  after  sunset . So there's no reason to think that either of the two scenarios in (C) will lead to more or less sun exposure than the other.

In other words, the "prolonged darkness" and "exposure to sunlight" are the same (as far as we know) in either scenario. So the passage actually supports that the amount of pigweed growth should be roughly  equal  in those two scenarios. The passage does not support that we'd see less pigweed growth in the first scenario, so (C) can be safely eliminated.

(A), on the other hand presents two scenarios that are very different, at least in terms of "exposure to sunlight":

1. Plow the field at night --> little/no exposure to sunlight --> little/no germination

2. Plow the field during the day --> exposure to sunlight --> germination

So (A) is strongly supported by the passage.

When soil is plowed in the spring, pigweed seeds that have been buried

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When soil is plowed in the spring, pigweed seeds that have been buried

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