GMAT RC CHALLENGE – 36 Hardest Official GMAT RC Passages of all time (P25/36)

Tiếp tục series 36 hardest GMAT RC passages, hôm nay chúng ta hãy thử sức với bài đọc số 25 nhé. 

Để đạt được hiệu quả tối đa khi đọc bài chia sẻ này, các bạn vui lòng:

Bước 1: Vào link gmatclub để làm bài đọc

Bước 2: Check lại đáp án của mình với quick explanations tại bài viết này

Passage 25/36: In strongly territorial birds such as the indigo bunting, song is the main mechanism for securing, defining, and defending an adequate breeding area…

LINK BÀI ĐỌC TẠI ĐÂY

RECAP các bước làm bài

Bước 1: Đọc bài đọc và dừng lại vài giây tóm tắt ý chính ngay sau mỗi đoạn nhỏ

Bước 2: Phát biểu Main Point / Primary Purpose hay nội dung chính của bài

Bước 3: Đọc câu hỏi, xác định vị trí liên quan trong Passage và Pre-think đáp án (Tuyệt đối không đọc đáp án trước, trừ khi câu hỏi không gợi ý được ta cần xem lại phần nào trong Passage HOẶC bạn đã nhớ rõ Passage như in)

Bước 4: Đọc nhanh answer choices và chọn đáp án gần với Pre-think nhất

Bây giờ, chúng ta cùng giải Passage 25/36 nhé!

Đáp án Passage 25/36

Summary

Para 1: Introduce a natural phenomenon, the song of the male indigo bunting and its function

Cụ thể:

• In strongly territorial birds such as the indigo bunting, song is the main mechanism for securing, defining, and defending an adequate breeding area. When population density is high, only the strongest males can retain a suitable area. The weakest males do not breed or are forced to nest on poor or marginal territories.

Para 2: Components and characteristics of the songs

Cụ thể:

• During the breeding season, the male indigo bunting sings in his territory; each song lasts two or three seconds with a very short pause between songs. Melodic and rhythmic characteristics are produced by rapid changes in sound frequency and some regularity of silent periods between sounds. These modulated sounds form recognizable units, called figures, each of which is reproduced again and again with remarkable consistency.
• Despite the large frequency range of these sounds and the rapid frequency changes that the bird makes, the number of figures is very limited. Further, although we found some unique figures in different geographical populations, more than 90 percent of all the figures of birds from different regions are alike.
• Indigo bunting figures are extremely stable on a geo- graphic basis. In our studies of isolated buntings we found that male indigo buntings are capable of singing many more types of figures than they usually do. Thus, it would seem that they copy their figures from other buntings they hear singing.

Para 3: Ability to distinguish songs of its own species from those of other species.

Cụ thể:

Realizing that the ability to distinguish the songs of one species from those of another could be an important factor in the evolution of the figures, we tested species recognition of a song.

• When we played a tape recording of a lazuli bunting or a painted bunting, male indigo buntings did not respond, even when a dummy of a male indigo bunting was placed near the tape recorder.
• Playing an indigo bunting song, however, usually brought an immediate response, making it clear that a male indigo bunting can readily distinguish songs of its own species from those of other species.

Para 4: Role of the song figures in intraspecies recognition

Cụ thể:

• The role of the song figures in intraspecies recognition was then examined . We created experimental songs composed of new figures by playing a normal song backwards, which changed the detailed forms of the figures without altering frequency ranges or gross temporal features. Since the male indigos gave almost a full response to the backward song, we concluded that a wide range of figure shapes can evoke positive responses.
• It seems likely, therefore, that a specific configuration is not essential for intraspecies recognition’ but it is clear that song figures must conform to a particular frequency range, must be within narrow limits of duration, and must be spaced at particular intervals.

Para 5: New figures with specific characteristics – a valuable adaptation for survival.

Cụ thể:

• There is evidence that new figures may arise within a population through a slow process of Change and selection. This variety is probably a valuable adaptation for survival: if every bird sang only a few types of figures, in dense woods or underbrush a female might have difficulty recognizing her mate’s song, and a male might not be able to distinguish a neighbor from a stranger. Our studies led us to conclude that there must be a balance between song stability and conservatism, which lead to clear-cut species recognition, and song variation which leads to individual recognition.

Main point: Analysis of songs of the male indigo bunting

Câu 1: The primary purpose of the passage is to

Prethink: Main point = Analysis of songs of the male indigo bunting

Vậy đáp án đúng là E. analyze a phenomenon

Câu 2: According to the passage, which of the following is true about the number and general nature of figures sung by the indigo bunting?

Prethink: Ở para 2, ta có:

• Despite the large frequency range of these sounds and the rapid frequency changes that the bird makes, the number of figures is very limited.
• Further, although we found some unique figures in different geographical populations, more than 90 percent of all the figures of birds from different regions are alike.
• Indigo bunting figures are extremely stable on a geographic basis. In our studies of isolated buntings we found that male indigo buntings are capable of singing many more types of figures than they usually do. Thus, it would seem that they copy their figures from other buntings they hear singing.

Vậy đáp án đúng là C. They are learned from other indigo buntings.

Câu 3: It can be inferred that the investigation that determined the similarity among more than 90 percent of all the figures produced by birds living in different regions was undertaken to answer which of the following questions?

Prethink: Ta cần xét từng câu hỏi và tìm đáp câu trả lời nếu có ở para 2 như sau:

I . How much variation, if any, is there in the figure types produced by indigo buntings in different locales?

. Further, although we found some unique figures in different geographical populations, more than 90 percent of all the figures of birds from different regions are alike. Indigo bunting figures are extremely stable on a geographic basis.

–> Not much variation –> Có trả lời được –> Giữ lại

II . Do local populations of indigo buntings develop their own dialects of figure types?

• although we found some unique figures in different geographical populations

–> Có –> Có trả lời được –> Giữ lại

III  . Do figure similarities among indigo buntings decline with increasing geographic separation?

• Indigo bunting figures are extremely stable on a geo- graphic basis.

–> Không có –> Có trả lời được –> Giữ lại

Vậy đáp án đúng là E. I, II, and III

Câu 4:  It can be inferred from the passage that the existence of only a limited number of indigo bunting figures serves primarily to

Prethink:

Ở para 3, ta có:

• male indigo buntings did not respond, even when a dummy of a male indigo bunting was placed near the tape recorder.
•  usually brought an immediate response, making it clear that a male indigo bunting can readily distinguish songs of its own species from those of other species.

Ở para 5 ta có:

• Our studies led us to conclude that there must be a balance between song stability and conservatism, which lead to clear-cut species recognition

Vậy đáp án đúng là C. enhances spices recognition by decreasing the number of figure patterns to which the bird must respond (tức limited number of figures để giúp nhận diện được đúng loài của mình)

Extra notes:

A . ensure species survival by increasing competition among the fittest males for the females

. Không có thông tin kết nối giữa limited number of figures và competition của males

–> Loại

B . increase population density by eliminating ambiguity in the figures to which the females must respond

• Không có thông tin này trong bài –> Loại

1. maintain the integrity of the species by restricting the degree of figure variation and change

• Ở para 5 ta có: new figures may arise within a population through a slow process of Change and selection. This variety is probably a valuable adaptation for survival

–> Loại

E . avoid confusion between species by clearly demarcating the figure patterns of each species

• Ở para 4, ta có: that a specific configuration is not essential for intraspecies recognition nên vẫn có thể có confusion.

–> Loại

Câu 5: It can be inferred that a dummy of a male indigo bunting was placed near the tape recorder that played the songs of different species in order to try to

Prethink: Ở para 3, ta có:

• When we played a tape recording of a lazuli bunting or a painted bunting, male indigo buntings did not respond, even when a dummy of a male indigo bunting was placed near the tape recorder.

–> Như vậy, đưa con dummy vào để thử xem male indigo buntings có nhận dạng dựa trên hình ảnh hay không và câu trả lời là không, nó dựa trên song hơn.

Vậy đáp án đúng là B. rule out visual cues as a factor in species recognition

Câu 6:  According to the passage , the authors played a normal indigo bunting song backwards in order to determine which of the following?

Prethink: Ở para 4, ta có:

• • We created experimental songs composed of new figures by playing a normal song backwards, which changed the detailed forms of the figures WITHOUT altering frequency ranges or gross temporal features.
  • Since the male indigos gave almost a full response to the backward song, we concluded that a wide range of figure shapes can evoke positive responses.

• that a specific configuration is not essential for intraspecies recognition’ but it is clear that song figures must conform to a particular frequency range, must be within narrow limits of duration, and must be spaced at particular intervals.

–> Như vậy, thí nghiệm này chỉ thay đổi figure shapes mà không thay đổi frequency ranges hay những vấn đề liên quan thời gian / temporal (duration hay intervals) để tìm hiểu về phản ứng của indigo buntings

Vậy đáp án đúng phải là C. How specific must a figure shape be for it to be recognized by the indigo bunting?

Câu 7: According to the passage , the indigo buntings’ songs function in which of the following ways?

Prethink: Ta cần xem từng thông tin xem có được nhắc trong bài như là function của songs của male indigo buntings hay không?

I . To delineate a breeding area

II . To defend a breeding area

• Ở para 1, ta đã có: song is the main mechanism for securing, defining, and defending an adequate breeding area nên I và II đúng –> Giữ lại I và II

III . To identify the birds to their mates

• Ở para cuối, ta có: there must be a balance between song stability and conservatism, which lead to clear-cut species recognition, and song variation which leads to individual recognition nên III cũng đúng vì songs giúp phân biệt loài và chim cái cũng phân biệt được songs của bạn tình với songs của các loài chim khác –> Giữ lại

Vậy đáp án đúng là E. I, II, and III

Hẹn gặp lại các bạn trong bài chia sẻ kì tới! Mọi thắc mắc liên quan đến các đáp án sai trong từng câu hỏi, các bạn có thể để lại comments bên dưới nhé.

P/s: Bài giải gợi ý trong series này chủ yếu tập trung cải thiện phần Pre-think, tức ta luôn cố gắng hết sức để tự nghĩ trước câu trả lời đúng rồi tìm đáp án gần nhất trong 5 answer choices.

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