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In the Sonoran Desert of northwestern Mexico and southern Arizona, t

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In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post Updated on: 03 Aug 2019, 02:40
13
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58
Question 1
00:00
A
B
C
D
E

based on 2033 sessions

72% (03:20) correct 28% (03:17) wrong

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Question 2
00:00
A
B
C
D
E

based on 2649 sessions

71% (01:41) correct 29% (02:02) wrong

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Question 3
00:00
A
B
C
D
E

based on 2567 sessions

51% (01:19) correct 49% (01:34) wrong

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Line
    In the Sonoran Desert of northwestern Mexico and
    southern Arizona, the flowers of several species of
    columnar cacti—cardon, saguaro, and organ
    pipe—were once exclusively pollinated at night by
(5)
    nectar-feeding bats, as their close relatives in arid
    tropical regions of southern Mexico still are. In these
    tropical regions, diurnal (daytime) visitors to columnar
    cactus flowers are ineffective pollinators because,
    by sunrise, the flowers' stigmas become unreceptive
(10)
    or the flowers close. Yet the flowers of the Sonoran
    Desert cacti have evolved to remain open after sunrise,
    allowing pollination by such diurnal visitors as bees and
    birds. Why have these cacti expanded their range of
    pollinators by remaining open and receptive in daylight?


(15)
    This development at the northernmost range of
    columnar cacti may be due to a yearly variation in the
    abundance—and hence the reliability—of migratory
    nectar-feeding bats. Pollinators can be unreliable
    for several reasons. They can be dietary generalists
(20)
    whose fidelity to a particular species depends on
    the availability of alternative food sources. Or, they
    can be dietary specialists, but their abundance may
    vary widely from year to year, resulting in variable
    pollination of their preferred food species. Finally, they
(25)
    may be dietary specialists, but their abundance may
    be chronically low relative to the availability of flowers.
    Recent data reveals that during spring in the
    Sonoran Desert, the nectar-feeding bats are
    specialists feeding on cardon, saguaro, and
(30)
    organpipe flowers. However, whereas cactus-flower
    abundance tends to be high during spring, bat
    population densities tend to be low except near
    maternity roosts. Moreover, in spring, diurnal cactus-
    pollinating birds are significantly more abundant in
(35)
    this region than are the nocturnal bats. Thus, with bats
    being unreliable cactus-flower pollinators, and daytime
    pollinators more abundant and therefore more reliable,
    selection favors the cactus flowers with traits that
    increase their range of pollinators. While data suggest
(40)
    that population densities of nectar-feeding bats are
    also low in tropical areas of southern Mexico, where
    bats are the exclusive pollinators of many species
    of columnar cacti, cactus-flower density and bat
    population density appear to be much more evenly
(45)
    balanced there: compared with the Sonoran Desert's
    cardon and saguaro, columnar cacti in southern Mexico
    produce far fewer flowers per night. Accordingly,
    despite their low population density, bats are able to
    pollinate nearly 100 percent of the available flowers.

(Book Question: 439)
The primary purpose of the passage is to
A. compare the adaptive responses of several species of columnar cacti in the Sonoran Desert with those in the arid tropical regions of southern Mexico
B. discuss some of the possible causes of the relatively low abundance of migratory nectar-feeding bats in the Sonoran Desert
C. provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert
D. present recent findings that challenge a particular theory as to why several species of columnar cacti in the Sonoran Desert have expanded their range of pollinators
E. compare the effectiveness of nocturnal and diurnal pollination for several different species of columnar cacti in the Sonoran Desert

(Book Question: 440)
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
A. A dietary specialist whose abundance is typically high in relation to that of the flower
B. A dietary specialist whose abundance is at times significantly lower than that of the flower
C. A dietary generalist for whom that flower’s nectar is not a preferred food but is the most consistently available food
D. A dietary generalist for whom that flower’s nectar is slightly preferred to other available foods
E. A dietary generalist that evolved from a species of dietary specialists

(Book Question: 441)
According to the passage, present-day columnar cacti in the Sonoran Desert differ from their close relatives in southern Mexico in that the Sonoran cacti
A. have flowers that remain open after sunset
B. are pollinated primarily by dietary specialists
C. can be pollinated by nectar-feeding bats
D. have stigmas that are unreceptive to pollination at night
E. are sometimes pollinated by diurnal pollinators




OG 2019 ID's
RC00633-01
RC00633-02
RC00633-06

Originally posted by AbdurRakib on 14 Jun 2017, 02:06.
Last edited by SajjadAhmad on 03 Aug 2019, 02:40, edited 2 times in total.
Updated complete topic (54).
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 14 Oct 2017, 07:00
12
1
hoangphuc wrote:
craveyourave wrote:
TheMechanic wrote:
Time Taken: 9.43mins
Score: 3/3.

Let me know if there are any open queries pertaining to any question in the passage. I would be more than happy to share my insights.


Hello,

Can you explain why is option E right for Q-3. I marked answer A.

In the Sonoran Desert of northwestern Mexico and southern Arizona, the owers of several species of columnar cacti—cardon, saguaro, and organ pipe—were once exclusively pollinated at night by nectar-feeding bats, as their close relatives in arid tropical regions of southern Mexico still are.

Does this suggest that cacti species in the south still depend on the night pollination.

Really confused!


Me too, I don't know why answer A in Question 3 is wrong
Passage clearly states that "Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise"


A is incorrect because of one word only: sunset. The passage says the flowers remain open after SUNRISE (during the day) not after SUNSET (during the night).
E. The passage clears states that "Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise, allowing pollination by such diurnal
visitors as bees and birds."
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 06 Jul 2017, 08:27
7
Very good passage. All correct but took 8 minutes to solve :shock:

The primary purpose of the passage is to
A. compare the adaptive responses of several species of columnar cacti in the Sonoran Desert with those in the arid tropical regions of southern Mexico
B. discuss some of the possible causes of the relatively low abundance of migratory nectar-feeding bats in the Sonoran Desert
C. provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert
D. present recent findings that challenge a particular theory as to why several species of columnar cacti in the Sonoran Desert have expanded their range of pollinators
E. compare the effectiveness of nocturnal and diurnal pollination for several different species of columnar cacti in the Sonoran Desert

Straight forward C. End of first paragraph pitches it clearly and rest of the passage tries to answer the question.
Quote:
Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise, allowing pollination by such diurnal visitors as bees and birds. Why have these cacti expanded their range of pollinators by remaining open and receptive in daylight?


(Book Question: 440)
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
A. A dietary specialist whose abundance is typically high in relation to that of the flower
B. A dietary specialist whose abundance is at times significantly lower than that of the flower
C. A dietary generalist for whom that flower’s nectar is not a preferred food but is the most consistently available food
D. A dietary generalist for whom that flower’s nectar is slightly preferred to other available foods
E. A dietary generalist that evolved from a species of dietary specialists

Quote:
Recent data reveals that during spring in the Sonoran Desert, the nectar-feeding bats are specialists feeding on cardon, saguaro, and organpipe flowers. However, whereas cactus-flower abundance tends to be high during spring, bat population densities tend to be low except near maternity roosts.


(Book Question: 441)
According to the passage, present-day columnar cacti in the Sonoran Desert differ from their close relatives in southern Mexico in that the Sonoran cacti
A. have flowers that remain open after sunset
B. are pollinated primarily by dietary specialists
C. can be pollinated by nectar-feeding bats
D. have stigmas that are unreceptive to pollination at night
E. are sometimes pollinated by diurnal pollinators
Quote:
In these tropical regions, diurnal (daytime) visitors to columnar cactus flowers are ineffective pollinators because,]by sunrise, the flowers' stigmas become unreceptive or the flowers close.Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise, allowing pollination by such diurnal visitors as bees and birds.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 30 Jul 2017, 02:50
1
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
A. A dietary specialist whose abundance is typically high in relation to that of the flower
B. A dietary specialist whose abundance is at times significantly lower than that of the flower
C. A dietary generalist for whom that flower’s nectar is not a preferred food but is the most consistently available food
D. A dietary generalist for whom that flower’s nectar is slightly preferred to other available foods
E. A dietary generalist that evolved from a species of dietary specialists

Is the OA really B
in B: A dietary specialist whose abundance is at times significantly lower than that of the flower
Evidence: Finally, they may be dietary specialists, but their abundance may be chronically low relative to the availability of flowers.
At times and chronically are clearly different.

In my opinion, the answer is C for the following evidence
in C: dietary generalist for whom that flower’s nectar is not a preferred food but is the most consistently available food
evidence: they can be dietary generalists whose fidelity to a particular species depends on the availability of alternative food sources
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 30 Jul 2017, 03:02
2
According to the passage, present-day columnar cacti in the Sonoran Desert differ from their close relatives in southern Mexico in that the Sonoran cacti
A. have flowers that remain open after sunset
B. are pollinated primarily by dietary specialists
C. can be pollinated by nectar-feeding bats
D. have stigmas that are unreceptive to pollination at night
E. are sometimes pollinated by diurnal pollinators
Quote:
In these tropical regions, diurnal (daytime) visitors to columnar cactus flowers are ineffective pollinators because,]by sunrise, the flowers' stigmas become unreceptive or the flowers close.Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise, allowing pollination by such diurnal visitors as bees and birds.
[/quote]

i think that the reson for choice E is not from : Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise, allowing pollination by such diurnal visitors as bees and birds.
but from: While data suggest that population densities of nectar-feeding bats are also low in tropical areas of southern Mexico, where bats are the exclusive pollinators of many species of columnar cacti
it means that in sounthern bats are exclusively pollinator and diurnal can not be pollinator. So Sonoran cacti can be pollinated by diurnal but their close relative in sounthern mexico cannot be.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 06 Sep 2017, 07:22
Hey AbdurRakib

Hope you are doing good :-)
I have the below 2 requests with respect to the RC you posted

1. The below paragraph is mentioned twice in the passage. Can you format the passage?
Quote:
that population densities of nectar-feeding bats are
also low in tropical areas of southern Mexico, where
bats are the exclusive pollinators of many species
of columnar cacti, cactus-flower density and bat
population density appear to be much more evenly


2. Can you post the OA to all questions? Seems like there is some confusion here and OA is missing for one of the questions

CC: sallysea
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 06 Sep 2017, 08:19
1
Please explain why main theme is C.
Because the last paragraph talks about comparing adaptations of Sonoran desert cacti species and southern Mexico cacti species
I think answer to theme question is A.

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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 11 Oct 2017, 09:25
1
sunny91 wrote:
TheMechanic wrote:
Time Taken: 9.43mins
Score: 3/3.

Let me know if there are any open queries pertaining to any question in the passage. I would be more than happy to share my insights.


Hi, can you explain the answer to the first question? primary purpose of the passage



The essence of the passage can be derived from this line:
"Why have these cacti expanded their range of pollinators by remaining open and receptive in daylight?"

Beyond this line, the passage is trying to answer this query. Read again and it will become clear.

And then read again option C : C. provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert

It is like matching 1:1. Does that help?
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 12 Oct 2017, 21:07
AbdurRakib wrote:
OG 2018 New RC
Line
    In the Sonoran Desert of northwestern Mexico and
    southern Arizona, the flowers of several species of
    columnar cacti—cardon, saguaro, and organ
    pipe—were once exclusively pollinated at night by
(5)
    nectar-feeding bats, as their close relatives in arid
    tropical regions of southern Mexico still are. In these
    tropical regions, diurnal (daytime) visitors to columnar
    cactus flowers are ineffective pollinators because,
    by sunrise, the flowers' stigmas become unreceptive
(10)
    or the flowers close. Yet the flowers of the Sonoran
    Desert cacti have evolved to remain open after sunrise,
    allowing pollination by such diurnal visitors as bees and
    birds. Why have these cacti expanded their range of
    pollinators by remaining open and receptive in daylight?


(15)
    This development at the northernmost range of
    columnar cacti may be due to a yearly variation in the
    abundance—and hence the reliability—of migratory
    nectar-feeding bats. Pollinators can be unreliable
    for several reasons. They can be dietary generalists
(20)
    whose fidelity to a particular species depends on
    the availability of alternative food sources. Or, they
    can be dietary specialists, but their abundance may
    vary widely from year to year, resulting in variable
    pollination of their preferred food species. Finally, they
(25)
    may be dietary specialists, but their abundance may
    be chronically low relative to the availability of flowers.
    Recent data reveals that during spring in the
    Sonoran Desert, the nectar-feeding bats are
    specialists feeding on cardon, saguaro, and
(30)
    organpipe flowers. However, whereas cactus-flower
    abundance tends to be high during spring, bat
    population densities tend to be low except near
    maternity roosts. Moreover, in spring, diurnal cactus-
    pollinating birds are significantly more abundant in
(35)
    this region than are the nocturnal bats. Thus, with bats
    being unreliable cactus-flower pollinators, and daytime
    pollinators more abundant and therefore more reliable,
    selection favors the cactus flowers with traits that
    increase their range of pollinators. While data suggest
(40)
    that population densities of nectar-feeding bats are
    also low in tropical areas of southern Mexico, where
    bats are the exclusive pollinators of many species
    of columnar cacti, cactus-flower density and bat
    population density appear to be much more evenly
(40)
    that population densities of nectar-feeding bats are
    also low in tropical areas of southern Mexico, where
    bats are the exclusive pollinators of many species
    of columnar cacti, cactus-flower density and bat
    population density appear to be much more evenly
(45)
    balanced there: compared with the Sonoran Desert's
    cardon and saguaro, columnar cacti in southern Mexico
    produce far fewer flowers per night. Accordingly,
    despite their low population density, bats are able to
    pollinate nearly 100 percent of the available flowers.

(Book Question: 439)
The primary purpose of the passage is to
A. compare the adaptive responses of several species of columnar cacti in the Sonoran Desert with those in the arid tropical regions of southern Mexico
B. discuss some of the possible causes of the relatively low abundance of migratory nectar-feeding bats in the Sonoran Desert
C. provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert
D. present recent findings that challenge a particular theory as to why several species of columnar cacti in the Sonoran Desert have expanded their range of pollinators
E. compare the effectiveness of nocturnal and diurnal pollination for several different species of columnar cacti in the Sonoran Desert

(Book Question: 440)
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
A. A dietary specialist whose abundance is typically high in relation to that of the flower
B. A dietary specialist whose abundance is at times significantly lower than that of the flower
C. A dietary generalist for whom that flower’s nectar is not a preferred food but is the most consistently available food
D. A dietary generalist for whom that flower’s nectar is slightly preferred to other available foods
E. A dietary generalist that evolved from a species of dietary specialists

(Book Question: 441)
According to the passage, present-day columnar cacti in the Sonoran Desert differ from their close relatives in southern Mexico in that the Sonoran cacti
A. have flowers that remain open after sunset
B. are pollinated primarily by dietary specialists
C. can be pollinated by nectar-feeding bats
D. have stigmas that are unreceptive to pollination at night
E. are sometimes pollinated by diurnal pollinators




The numbering of questions and OA is off.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 14 Oct 2017, 04:30
TheMechanic wrote:
Time Taken: 9.43mins
Score: 3/3.

Let me know if there are any open queries pertaining to any question in the passage. I would be more than happy to share my insights.


Hello,

Can you explain why is option E right for Q-3. I marked answer A.

In the Sonoran Desert of northwestern Mexico and southern Arizona, the owers of several species of columnar cacti—cardon, saguaro, and organ pipe—were once exclusively pollinated at night by nectar-feeding bats, as their close relatives in arid tropical regions of southern Mexico still are.

Does this suggest that cacti species in the south still depend on the night pollination.

Really confused!
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 14 Oct 2017, 05:36
craveyourave wrote:
TheMechanic wrote:
Time Taken: 9.43mins
Score: 3/3.

Let me know if there are any open queries pertaining to any question in the passage. I would be more than happy to share my insights.


Hello,

Can you explain why is option E right for Q-3. I marked answer A.

In the Sonoran Desert of northwestern Mexico and southern Arizona, the owers of several species of columnar cacti—cardon, saguaro, and organ pipe—were once exclusively pollinated at night by nectar-feeding bats, as their close relatives in arid tropical regions of southern Mexico still are.

Does this suggest that cacti species in the south still depend on the night pollination.

Really confused!


Me too, I don't know why answer A in Question 3 is wrong
Passage clearly states that "Yet the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise"
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 17 Nov 2017, 09:01
Can someone please correct the formatting of the passage. The information has been repeated within the passage.

Moreover can soeone explain why B is preferred over C in Q2
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 17 Nov 2017, 09:33
anurag16 wrote:
Can someone please correct the formatting of the passage. The information has been repeated within the passage.

Moreover can soeone explain why B is preferred over C in Q2


Excerpt from the passage line 25
"Finally, they may be dietary specialists, but their abundance may be chronically low relative to the availability of flowers "
B conveys the same saying that when the specialist population is very low compared to that of flowers, the specialists are unreliable. There aren't enough pollinators even if those specialist pollinators will prefer the particular flower over others. They could have been relied on for pollination had they been in abundance compared to the population of flowers.

C talks about generalists- who don't have a particular choice and pollinate any flower depending on its availability - are the first to exhibit fidelity (uselessness) in pollination of a particular flower.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 09 Feb 2018, 07:18
soumya170293 wrote:
Would anyone please explain the POE of A for the question 3 ?
Seemed tough passage.


In my opinion, A is incorrect because the first sentence of the passage says: "In the Sonoran Desert of northwestern Mexico and southern Arizona, the flowers of several species of columnar cacti—cardon, saguaro, and organ pipe—were once exclusively pollinated at night by nectar-feeding bats, as their close relatives in arid tropical regions of southern Mexico still are." => this means they are both have flowers that remain open after sunset, so this can't be a difference between these two.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 10 May 2018, 15:51
1
P1 - some cacti evolved from night time to day time pollination.
P2 - reasons given for situation defined in p1.

The primary purpose of the passage is to
A. compare the adaptive responses of several species of columnar cacti in the Sonoran Desert with those in the arid tropical regions of southern Mexico - p2
B. discuss some of the possible causes of the relatively low abundance of migratory nectar-feeding bats in the Sonoran Desert - P2/2
C. provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert - Most accurate among all.
D. present recent findings that challenge a particular theory as to why several species of columnar cacti in the Sonoran Desert have expanded their range of pollinators - challenge a theory is not there, its a simple explanation.
E. compare the effectiveness of nocturnal and diurnal pollination for several different species of columnar cacti in the Sonoran Desert -- Passage is certainly not about this.
------------------------------------------------

(Book Question: 440)
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
Lines to read - cactus-flower abundance tends to be high during spring, bat population densities tend to be low except near maternity roosts.
B. A dietary specialist whose abundance is at times significantly lower than that of the flower - correct.

------------------------------------------------
(Book Question: 441)
According to the passage, present-day columnar cacti in the Sonoran Desert differ from their close relatives in southern Mexico in that the Sonoran cacti

E. are sometimes pollinated by diurnal pollinators - the flowers of the Sonoran Desert cacti have evolved to remain open after sunrise, allowing pollination by such diurnal visitors as bees and birds.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 03 Oct 2018, 21:56
AbdurRakib wrote:
Line
    In the Sonoran Desert of northwestern Mexico and
    southern Arizona, the flowers of several species of
    columnar cacti—cardon, saguaro, and organ
    pipe—were once exclusively pollinated at night by
(5)
    nectar-feeding bats, as their close relatives in arid
    tropical regions of southern Mexico still are. In these
    tropical regions, diurnal (daytime) visitors to columnar
    cactus flowers are ineffective pollinators because,
    by sunrise, the flowers' stigmas become unreceptive
(10)
    or the flowers close. Yet the flowers of the Sonoran
    Desert cacti have evolved to remain open after sunrise,
    allowing pollination by such diurnal visitors as bees and
    birds. Why have these cacti expanded their range of
    pollinators by remaining open and receptive in daylight?


(15)
    This development at the northernmost range of
    columnar cacti may be due to a yearly variation in the
    abundance—and hence the reliability—of migratory
    nectar-feeding bats. Pollinators can be unreliable
    for several reasons. They can be dietary generalists
(20)
    whose fidelity to a particular species depends on
    the availability of alternative food sources. Or, they
    can be dietary specialists, but their abundance may
    vary widely from year to year, resulting in variable
    pollination of their preferred food species. Finally, they
(25)
    may be dietary specialists, but their abundance may
    be chronically low relative to the availability of flowers.
    Recent data reveals that during spring in the
    Sonoran Desert, the nectar-feeding bats are
    specialists feeding on cardon, saguaro, and
(30)
    organpipe flowers. However, whereas cactus-flower
    abundance tends to be high during spring, bat
    population densities tend to be low except near
    maternity roosts. Moreover, in spring, diurnal cactus-
    pollinating birds are significantly more abundant in
(35)
    this region than are the nocturnal bats. Thus, with bats
    being unreliable cactus-flower pollinators, and daytime
    pollinators more abundant and therefore more reliable,
    selection favors the cactus flowers with traits that
    increase their range of pollinators. While data suggest
(40)
    that population densities of nectar-feeding bats are
    also low in tropical areas of southern Mexico, where
    bats are the exclusive pollinators of many species
    of columnar cacti, cactus-flower density and bat
    population density appear to be much more evenly
(45)
    balanced there: compared with the Sonoran Desert's
    cardon and saguaro, columnar cacti in southern Mexico
    produce far fewer flowers per night. Accordingly,
    despite their low population density, bats are able to
    pollinate nearly 100 percent of the available flowers.
(Book Question: 439)
The primary purpose of the passage is to
A. compare the adaptive responses of several species of columnar cacti in the Sonoran Desert with those in the arid tropical regions of southern Mexico
B. discuss some of the possible causes of the relatively low abundance of migratory nectar-feeding bats in the Sonoran Desert
C. provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert
D. present recent findings that challenge a particular theory as to why several species of columnar cacti in the Sonoran Desert have expanded their range of pollinators
E. compare the effectiveness of nocturnal and diurnal pollination for several different species of columnar cacti in the Sonoran Desert

(Book Question: 440)
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
A. A dietary specialist whose abundance is typically high in relation to that of the flower
B. A dietary specialist whose abundance is at times significantly lower than that of the flower
C. A dietary generalist for whom that flower’s nectar is not a preferred food but is the most consistently available food
D. A dietary generalist for whom that flower’s nectar is slightly preferred to other available foods
E. A dietary generalist that evolved from a species of dietary specialists

(Book Question: 441)
According to the passage, present-day columnar cacti in the Sonoran Desert differ from their close relatives in southern Mexico in that the Sonoran cacti
A. have flowers that remain open after sunset
B. are pollinated primarily by dietary specialists
C. can be pollinated by nectar-feeding bats
D. have stigmas that are unreceptive to pollination at night
E. are sometimes pollinated by diurnal pollinators




OG 2019 ID's
RC00633-01
RC00633-02
RC00633-06


Took 6:34 mins to complete.

Qn 439. The primary purpose of the passage is to...

Was confused between A and C, I eliminated A but not sure if my reasons are right. Please comment

A) compare the adaptive responses of several species of columnar cacti in the Sonoran Desert with those in the arid tropical regions of southern
Mexico -Adaptive response only in the Sonoran desert not in the southern mexico. Hence not true.

C) provide a possible explanation for a particular evolutionary change in certain species of columnar cacti in the Sonoran Desert.
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 21 Nov 2018, 15:19
Hi - How do you read a passage like this ? I got completely zapped after paragraph 3 as there are SO many technical terms unfortunately ...

I tried my hardest not to get involved in the details but in this passage -- isn't this something you to read to understand this passage

Normally i am good with reading RC but this one completely rocked me ....Please assist !
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New post 21 Nov 2018, 17:05
1
jabhatta@umail.iu.edu - I have summarize few things here, See if its helpful ? Main point is read for change in information and not for information. I say you
1. Go through link, make your own notes, choose what ever source you want.
2. Practice 2-4 RC daily. when I say practice, you need to apply your notes on the passage. once done try to read some OE if you can arrange or good replies on forum.
3. try to time yourself while doing it. Dont worry this will improve with time. time urself for max 4 question passage. Beyond that no point to time yourself.
4. if you make a mistake, find why you made that mistake. Lets categories problems
a. reading problem ?
b. question understanding problem,
C. once done with question, finding right text problem. - if not able to do this, problem with mapping the text. map what is in which paragraph.
D. POE problem - eliminate extreme choices straight. then POE. start looking back to passage when you left with 2-3 choices. rem you need to find 4 wrong one.

https://gmatclub.com/forum/my-notes-rea ... 75525.html
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 22 Nov 2018, 21:58
Hey,

One way to manage time and read passages effectively is to read what is important and what is not because you can solve 80% of the passage by reading 20% of the passage.

To know more about how you can read better, please check the youtube link below.

https://www.youtube.com/watch?v=43X5yJI ... c_0aAFpICK

All the very best.

Thanks,
Saikiran
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t  [#permalink]

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New post 27 Nov 2018, 02:50
Dear Verbal Expert,

even after reading the discussion I am still not able to fully understand Question 2... I understand why B is correct, but I do not understand why C is incorrect. Is it because of the "not a preferred food"? The passage never talks about explicitly about preference.

Thank you in advance!!!

(Book Question: 440)
According to the passage, which of the following types of nectar-feeding pollinators is likely to be an unreliable pollinator of a particular cactus flower?
A. A dietary specialist whose abundance is typically high in relation to that of the flower
B. A dietary specialist whose abundance is at times significantly lower than that of the flower
C. A dietary generalist for whom that flower???s nectar is not a preferred food but is the most consistently available food
D. A dietary generalist for whom that flower???s nectar is slightly preferred to other available foods
E. A dietary generalist that evolved from a species of dietary specialists
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Re: In the Sonoran Desert of northwestern Mexico and southern Arizona, t   [#permalink] 27 Nov 2018, 02:50

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