Reading 1

[سیندخت 18,785]

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The following passage is an excerpt from an article written by a zoologist

 

. Ever since the giant panda was discovered in the middle of the nineteenth century, a controversy has raged over its relation to other species. While the general public tends to view the giant panda as a kind of living teddy bear, biologists have not been sure how to classify this enigmatic animal. At different times, the panda has been placed alternately with bears in the Ursidae family, with raccoons in the Procyonidae family, and in its own "Ailuropodidae" family. Biologists who classify animal species have tried to categorize the panda according to whether its traits are "homologous" or merely "analogous" to similar traits in other species. Homologous traits are those which species have in common because they have descended from a common ancestor. For instance, every species of cat has the homologous trait of possessing only four toes on its hind foot, because every member of the cat family descended from a common feline ancestor. The greater the number of such traits that two species share, the more closely they are related. A cat and a lion have more homologous traits between them than a cat and a human, for example—so cats and lions are more closely related, biologically

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What appears to be a homologous trait may only be an analogous trait, however. An analogous trait is a trait that two species have in common not because they are descended from a common ancestor but because they have different ancestors that developed in similar ways in response to their environment. The eagle and the butterfly, for example, both possess the trait of wings.

 

It is often difficult to distinguish homologous from analogous traits, which is why analysis of the panda's traits has raised more questions than it has answered. The panda may look like a bear, for example, but its appearance could just be an analogous trait; the panda also has many traits that bears do not possess. It has a more massive jaw than a bear since its diet consists primarily of bamboo. Giant pandas also have thumbs which are used to strip leaves from bamboo stalks. Bears do not have a similar digit. Furthermore, most bears growl or roar, but giant pandas bleat. Progress has been made on the panda mystery only through examination of its genetic material. Using a technique known as DNA hybridization, biologists have demonstrated that the giant panda is indeed a relative of the bear, but the relationship is distant indeed. Their most recent common ancestor lived over fifteen million years ago

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[سیندخت 18,785]

The primary purpose of the passage is to: 1

A : praise the work that has been done by biologists in the attempt to classify the panda.

 

B : draw attention to the fact that the giant panda is not really a species of bear.

 

C : discuss the difficulty of determining to whichcategory the giant panda belongs.

 

D : point out the similarities between the panda and certain other animal species.

 

E : prove that the giant panda has long been incorrectly classified.

 

 

2/ Which of the following is NOT possible using the homologous/analogous trait classification scheme?

A : Two species that share more than one homologous trait.

 

B : Two species that share more than one analogous trait.

 

C: Two species that share an analogous trait but have no common ancestor.

 

D: Two species that share a homologous trait but have no common ancestor.

 

E : Two species that share no analogous or homologous traits

 

 

3/ The author refers to "the eagle and the butterfly" in the third paragraph chiefly to illustrate that

A : many species have developed the means to fly

 

B : similar traits in two species do not necessarily indicate that they are related

 

C : the eagle and the butterfly may be descended from a common ancestor

 

D : all of animal life is not descended from a single common ancestor

 

E : there are diverse ways that animals can adapt to their environment

[سیندخت 18,785]

please read the answers after you answered the questions

Your eyes may see the answers befor answering the questions,

So I changed the colour of the answers in to white

 

answers :

 

 

1 : (E).This short humanities passage is about Dorothy Wordsworth and her relationship with her brother, William. More specifically it is about how that relationship affected her attitude to her own writing, and her view of herself as a writer.

The first paragraph gives you a big hint as to what the whole passage is about when it says "The important question is�." Take note of this. Not surprisingly, the entire second paragraph is spent answering this "important question." The main idea raised in paragraph #1 and discussed in paragraph #2 is "how [Dorothy and William's] relationship contributed to Dorothy's inability to conceive of herself as a writer." Answer choice (5) best summarizes the preceding quote.

 

 

 

 

 

2 : (D)

This is a Detail question, so you'll want to research the passage for the answer before going to the answer choices. The definitions of homologous and analogous traits are in the first sentences of the second and third paragraphs, respectively. To recap: homologous traits are those shared by species that have a common ancestor, whereas analogous traits are those shared by species that have developed in similar ways but that do not have a common ancestor. It is impossible, by definition, for two species to share a homologous trait if they do not have a common ancestor, so (D) is the correct choice.

 

 

 

3 . (B)

The reference to the eagle and the butterfly can be found at the end of the third paragraph. The overall purpose of this paragraph is to explain what an analogous trait is. The wings of the butterfly and the eagle are cited as an example. In other words, they have the same trait, but no common ancestor. (B) paraphrases the author's point and is correct. All of the other choices miss the overall idea of the paragraph (choice © is just plain wrong because the eagle and the butterfly are NOT descended from a common ancestor).