Even more than mountainside slides of mud or snow, naturally occurring

Question

Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees. Aspens' need for fire may seem illogical since aspens are particularly vulnerable to fires; whereas  the bark of most trees  consists of dead cells, the aspen's bark is a living, functioning tissue that―along with the rest of the tree―succumbs quickly to fire.

The explanation is that each aspen, while appearing to exist separately as a single tree, is in fact only the stem or shoot of a far larger organism. A group of thousands of aspens can actually constitute a single organism, called a clone, that shares an interconnected root system and a unique set of genes. Thus, when one aspen―a single stem―dies, the entire clone is affected. While alive, a stem sends hormones into the root system to suppress formation of further stems. But when the stem dies, its hormone signal also ceases. If a clone loses many stems simultaneously, the resulting hormonal imbalance triggers a huge increase in new, rapidly growing shoots that can outnumber the ones destroyed. An aspen grove needs to experience fire or some other  disturbance  regularly, or it will fail to regenerate and spread. Instead, coniferous trees will invade the aspen grove's borders and increasingly block out sunlight needed by the aspens.   1 
1. The primary purpose of the passage is to explain the

(A) qualities that make a particular organism unique
(B) evolutionary change undergone by a particular organism
(C) reasons that a phenomenon benefits a particular organism
(D) way in which two particular organisms compete for a resource
(E) means by which a particular organism has been able to survive in a barren region

2 
 2. It can be inferred from the passage that when aspen groves experience a " disturbance ", such a disturbance

(A) leads to a hormonal imbalance within an aspen clone
(B) provides soil conditions that are favorable for new shoots
(C) thins out aspen groves that have become overly dense
(D) suppresses the formation of too many new aspen stems
(E) protects aspen groves by primarily destroying coniferous trees rather than aspens

3 
 3. The author of the passage refers to " the bark of most trees " most likely in order to emphasize the

(A) vulnerability of aspens to damage from fire when compared to other trees
(B) rapidity with which trees other than aspens succumb to destruction by fire
(C) relatively great degree of difficulty with which aspens catch on fire when compared to other trees
(D) difference in appearance between the bark of aspens and that of other trees
(E) benefits of fire to the survival of various types of trees

4 
 4. According to the passage, which of the following would occur if an aspen failed to regenerate periodically?

(A) Individual aspens would cease to produce hormones.
(B) Individual aspens would grow outward instead of upward.
(C) The root system of the grove's clone would die.
(D) The grove would lose its access to sunlight.
(E) Soil conditions in the grove would become unfavorable for the growth of aspens.

bkkanurag · Accepted Answer

1)  C

A. qualities that make a particular organism unique
Here the author doesn't compare the qualities of Aspen trees with other trees or organisms to make it unique. He just just mentions them.  So not A

B. evolutionary change undergone by a particular organism.
The author doesn't mention any stages of evolution of the Aspen plant.  So not B .

C. reasons that a phenomenon benefits a particular organism 
 Correct answer  because the first paragraph introduces the importance of the phenomenon (forest fires) and the body paragraph explains the benefits of it.

D. way in which two particular organisms compete for a resource
The author doesn't draw a comparison between two trees. He mentions coniferous trees at the last only to explain what would happen if there were no forest fires.  SO not D

E. means by which a particular organism has been able to survive in a barren region
The author doesn't even mention that the trees are growing on barren lands.  So not E.

2) A

A. leads to a hormonal imbalance within an aspen clone 
 Correct answer  because the disturbance ( mainly forest fires) lead to hormonal imbalance which subsequently lead to new shoots of stems.

B. provides soil conditions that are favorable for new shoots
The author doesn't talk about soil conditions.  So not B

C. thins out aspen groves that have become overly dense
The disturbance thins out Aspen groves either thin or dense or otherwise. So cannot be the thinning of only dense groves.  So not C .

D. suppresses the formation of too many new aspen stems
Actually it aids the formation of new stems.  So not D .

E. protects aspen groves by primarily destroying coniferous trees rather than aspens
The disturbance only destroys Aspen trees. The author never even mentions forest fires destroying coniferous trees let alone protecting Aspen trees by destroying other trees. So not E.

3) A

A. vulnerability of aspens to damage from fire when compared to other trees 
 Correct answer  because Aspen trees have a living bark unlike most trees which succumbs to fire quickly as stated in the passage.

B. rapidity with which trees other than aspens succumb to destruction by fire
Actually the passage says the opposite about the other trees catching fire.  So not B

C. relatively great degree of difficulty with which aspens catch on fire when compared to other trees
Again the passage says that Aspen trees catch fire quickly in comparison to other trees.  So not C.

D. difference in appearance between the bark of aspens and that of other trees
The author doesn't talk about the appearance of the barks.  So not D .

E. benefits of fire to the survival of various types of trees
The author says that fires are important for Aspen trees alone but he doesn't mention any other trees whose survival is aided by forest fires.  So not E

4) D

A. Individual aspens would cease to produce hormones
The passage never mentions that the shoots would stop producing hormones. In fact it says the exact opposite.  So not A

B. Individual aspens would grow outward instead of upward.
The passage doesn't talk about the direction of the growth of the grove. So not B

C. The root system of the grove's clone would die.
The passage never says that the root system would die if it doesn't regenerate. It only says that it would cease to grow new shoots.

D. The grove would lose its access to sunlight 
 Correct answer  because if it doesn't produce new shoots, coniferous trees will invade the groves and block sunlight as mentioned in the last line of the passage.

E. Soil conditions in the grove would become unfavorable for the growth of aspens.
The author never talks about effect of regeneration on the soil conditions.  So not E

Skywalker18 · Answer

Took 4 mins 30 seconds, including 2 mins to read

1. The primary purpose of the passage is to explain the
C. reasons that a phenomenon benefits a particular organism - "Even more than mountainside slides of mud or snow, naturally occurring forest fires promote the survival of aspen trees"

2. It can be inferred from the passage that when aspen groves experience a "disturbance" , such a disturbance
A. leads to a hormonal imbalance within an aspen clone - But when the stem dies, its hormone signal also ceases. If a clone loses many stems simultaneously, the resulting hormonal imbalance triggers a huge increase in new, rapidly growing shoots that can outnumber the ones destroyed.

3. The author of the passage refers to "the bark of most trees" (line 6) most likely in order to emphasize the
A. vulnerability of aspens to damage from fire when compared to other trees - Correct

4. According to the passage, which of the following would occur if an aspen grove failed to regenerate periodically?
D. The grove would lose its access to sunlight - Correct - An aspen grove needs to experience fire or some other disturbance regularly, or it will fail to regenerate and spread. Instead, coniferous trees will invade the aspen grove's borders and increasingly block out sunlight needed by the aspens.

aragonn · Answer

P1 - tree problems with fire.
P2 - clone structure + why fire is helpful for tree.
Main point - a tree succumbs quickly with fire and it is important for its growth.

1. The primary purpose of the passage is to explain the

(A) qualities that make a particular organism unique - No
(B) evolutionary change undergone by a particular organism - No 
(C) reasons that a phenomenon benefits a particular organism - May be; well this one is best of the lot.
(D) way in which two particular organisms compete for a resource - No
(E) means by which a particular organism has been able to survive in a barren region - No

---------------------------------------------------
2. It can be inferred from the passage that when aspen groves experience a "disturbance", such a disturbance

(A) leads to a hormonal imbalance within an aspen clone - correct.
---------------------------------------------------
3. The author of the passage refers to "the bark of most trees" most likely in order to emphasize the

whereas the bark of most trees consists of dead cells, the aspen's bark is a living, functioning tissue that―along with the rest of the tree―succumbs quickly to fire.
(A) vulnerability of aspens to damage from fire when compared to other trees - may be
(B) rapidity with which trees other than aspens succumb to destruction by fire - no
(C) relatively great degree of difficulty with which aspens catch on fire when compared to other trees - No
(D) difference in appearance between the bark of aspens and that of other trees - No
(E) benefits of fire to the survival of various types of trees - too broad.

------------------------------------------------------

4. According to the passage, which of the following would occur if an aspen failed to regenerate periodically?
An aspen grove needs to experience fire or some other disturbance regularly, or it will fail to regenerate and spread. Instead, coniferous trees will invade the aspen grove's borders and increasingly block out sunlight needed by the aspens.

(D) The grove would lose its access to sunlight. - winner

woohoo921 · Answer

I would be so appreciative if an expert can explain the explanations for this passage. I also have specific questions below.

1. For "The primary purpose of the passage is to explain the" question:
Why exactly is Choice A (qualities that make a particular organism unique) incorrect? Choice A and C seem very similar.

2. For the "It can be inferred from the passage that when aspen groves experience a ???disturbance??? (see highlighted text), such a disturbance" question:
I see why A is the best choice because the other answers are not mentioned in the passage. However, if fire causes the disturbance, why is "fire or some other disturbance" listed as two separate things?

Thank you in advance!

GMATNinja · Answer

Question 1 
 
When answering a primary purpose question, ask yourself  why  the author is writing the passage. What is he/she trying to accomplish?

In the first paragraph the author tells us that aspens need fire, and that this is strange because they are vulnerable to fires. In the second paragraph, the author explains why aspens actually need fires.

So, why did the author write this passage? 
 
The author isn't trying to argue that the aspen is "unique." There could be other organisms that function in similar ways.

(A) is out.

(C) is better all around. First, what the author really cares about is why aspens (the "particular organism") need fire (the "phenomenon").

(C) is the correct answer choice to question 1.

Regarding your second question: a fire is a  type  of disturbance. The author mentions other examples of disturbances in the first sentence ("mountainside slides of mud or snow"). Aspens benefits more from fires, but also could benefits from these different types of disturbance. That's why the author says that aspen trees need "fire or some other disturbance."

I hope that helps!

VerbalBot · Answer

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Even more than mountainside slides of mud or snow, naturally occurring

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Even more than mountainside slides of mud or snow, naturally occurring

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