Passage 1
Scientists trying to determine where a starfish's head is have come to a startling conclusion: it is effectively the whole animal. This finding helps us understand how evolution generates the dramatic diversity of animal forms.
Starfish, also known as sea stars, belong to a group of animals called echinoderms, which includes sea urchins and sea cucumbers. Their strange body plans have long puzzled biologists. Most animals, including humans, have a distinct head end and tail end, with a line of symmetry running down the middle of their body, dividing it into two mirror-image halves. Animals with this two-sided symmetry are called bilaterians.
Echinoderms, on the other hand, have five lines of symmetry radiating from a central point and no physically obvious head or tail. Yet they are closely related to animals like us and evolved from a bilaterian ancestor. Even their larvae are bilaterally symmetrical, but radically reorganise their bodies as they metamorphose into adults.
Laurent Formery at Stanford University says, “The morphology cannot tell you anything, almost.” He and his colleagues decided to look at a set of genes known to direct the head-to-tail organisation of all bilaterians. In these animals, the genes are turned on, or expressed, in stripes in the outer layer of the developing embryo. The genes that are expressed in each stripe define which point on the head-to-tail axis it will become.
The team wanted to see if the gene expression patterns would reveal a “molecular anatomy” in starfish. To their surprise, the genes that determine the head end in bilaterians were expressed in a line running down the middle of each arm on the underside of a starfish. The next “head - most” genes were expressed on either side of this line. Even more strangely, the genes normally expressed in the trunk of bilaterians were missing in the outer layer of the starfish. This suggests that starfish have jettisoned their trunk regions and freed up the outer layer to evolve in new directions.
The findings show that “the body of an echinoderm, at least in terms of the external body surface, is essentially a head walking about on its lips on the seafloor,” says Thurston Lacalli at the University of Victoria in Canada.
What conclusion have scientists reached about starfish
A. Starfish have a clearly defined head and tail.
B. The whole starfish can be seen as its head.
C. Starfish evolved from a non - bilaterian ancestor.
D. Starfish larvae have no symmetry.
What is the difference between echinoderms and bilaterians
A. Echinoderms have a line of symmetry running down the middle of their body.
B. Bilaterians have five lines of symmetry radiating from a central point.
C. Echinoderms don't have an obvious head or tail physically.
D. Bilaterians' genes are expressed in a more complex way.
What did Formery's team find in their research on starfish
A. The gene expression patterns in starfish are the same as those in bilaterians.
B. The genes determining the head end in bilaterians were not expressed in starfish.
C. Starfish have developed new gene expression patterns in their trunk regions.
D. Some genes normally found in the trunk of bilaterians were absent in starfish's outer layer.
What can we infer from Thurston Lacalli's words
A. Starfish's body structure is unique in the animal kingdom.
B. Starfish use their heads to move on the seafloor.
C. Starfish have a more advanced body structure than bilaterians.
D. Starfish's body surface has a special function for protection.
Passage 2
Roosters show distinct behaviors when encountering another chicken compared to seeing their own reflection in a mirror. This difference hints that these birds might possess the ability to recognize themselves in a mirror, an important sign of self - awareness.
The traditional mirror self - recognition test, dating back to 1970, involves placing a mark on an animal's body in a spot only visible through its reflection. Researchers then observe if the animal touches or inspects the mark while looking at its mirror image. If it does, it implies that the animal understands the reflection represents its own body. Although few non - human species have passed this test, great apes, dolphins, elephants, and magpies are among them.
Recently, there have been claims that species like penguins, horses, cleaner wrasse fish, and manta rays have passed the test, but these claims are controversial. Sonja Hillemann from the University of Bonn in Germany and her colleagues suspected that many animals have little natural incentive to investigate such marks in the traditional test. So, they adjusted the test to align with the natural behavior of roosters. Roosters typically make loud alarm calls to alert other chickens of nearby predators but remain quiet when alone.
In the laboratory, the team tested 68 roosters one by one in an arena divided by a wire mesh. They placed a rooster on one side, either leaving the other side empty, putting another rooster there, or adding a mirror to the divider for some tests. To simulate a threat, they projected a hawk's silhouette on the arena ceiling.
The results showed that roosters could distinguish between a real rooster and its reflection through vision rather than smell or sound. What's more, since the roosters behaved similarly when alone and when facing their reflection, the researchers suggest that roosters may recognize that the reflection is of themselves. This discovery indicates that self - recognition may be more widespread among animals than previously thought.
What is the significance of the traditional mirror self - recognition test
A. It helps determine if an animal can recognize its friends.
B. It is used to check an animal's ability to react to threats.
C. It can prove whether an animal has self - awareness.
D. It shows an animal's understanding of its own body size.
Why did Sonja Hillemann and her team modify the self - recognition test for roosters
A. Because the traditional test was too difficult for roosters.
B. Because they thought the traditional test didn't suit roosters' natural behavior.
C. Because they wanted to test more animals in a different way.
D. Because roosters couldn't see the marks in the traditional test.
What did the new test on roosters find
A. Roosters can only distinguish reflections through smell.
B. Roosters always act differently when alone and with a reflection.
C. Self - recognition may be more common in animals than we thought.
D. All roosters can definitely recognize themselves in the mirror.
What can we infer from the passage
A. The traditional self - recognition test is completely useless.
B. More species may be able to recognize themselves than we know.
C. Roosters are the only non - ape animals that can pass the new test.
D. Animals' self - recognition ability has nothing to do with their survival.
Passage 3
Vaccines play a crucial role in safeguarding our health, and DNA vaccines are emerging as a promising new option. Michael Le Page states that vaccines containing DNA would be easier to store than mRNA alternatives and should be as effective as conventional vaccines with live viruses.
Medigen, a company, is seeking approval for the first human trials of DNA vaccines designed to produce live viruses in people's bodies. The goal is to combine the potential advantages of DNA vaccines, such as rapid manufacturing and easy storage, with the greater efficacy of vaccines that consist of live weakened viruses. “So instead of giving live virus, we would give a piece of DNA and the body will make the vaccine,” says Peter Pushko at Medigen in Frederick, Maryland.
Medigen has tested two potential vaccines in mice so far, one for chikungunya and one for yellow fever. The DNA vaccines protected the animals when they were later exposed to infection - causing viruses. The company plans to begin human trials next year. “I anticipate we would have the production and storage ease of DNA, but the potency of a live virus,” says Pushko. “As soon as we get the go - ahead from the FDA [US Food and Drug Administration], we will start testing in a phase 1 clinical trial.”
It's also possible for weakened viruses to revert to the dangerous form, which happens with the live polio vaccine, albeit rarely. Many modern vaccines consist of “dead” viruses that can't replicate or of viral proteins, rather than an entire virus, such as the human papillomavirus and hepatitis B vaccines. However, these vaccines typically require repeated doses to produce a strong enough response.
One potential advantage of DNA vaccines over mRNA ones is that the molecule is more stable. DNA vaccines can be kept in a fridge or even at room temperature, rather than needing to be kept frozen like most mRNA vaccines, says Pushko. DNA vaccines coding for live viruses help solve the delivery problem because once a few viruses are made, they start replicating themselves. So people get an effective dose even if relatively few DNA molecules reach the nuclei of cells.
What is special about DNA vaccines according to the passage
A. They are more effective than conventional vaccines.
B. They are the first vaccines to be tested on humans.
C. They are easier to store compared to some other vaccines.
D. They contain live weakened viruses for better protection.
What can we learn about Medigen's DNA vaccines
A. They have already been approved for human trials.
B. They have been tested on humans for chikungunya and yellow fever.
C. They aim to combine advantages of different vaccine types.
D. They can only be stored in a fridge or at room temperature.
Why are many modern vaccines made of “dead” viruses or viral proteins
A. Because they can replicate easily in the human body.
B. Because they are more potent than live virus vaccines.
C. Because they are less likely to revert to a dangerous form.
D. Because they don't require repeated doses.
What is one advantage of DNA vaccines over mRNA vaccines
A. They can make more viral proteins.
B. The DNA molecule is more stable.
C. They can produce a stronger response.
D. They can be made more quickly.Passage 1
Scientists trying to determine where a starfish's head is have come to a startling conclusion: it is effectively the whole animal. This finding helps us understand how evolution generates the dramatic diversity of animal forms.
Starfish, also known as sea stars, belong to a group of animals called echinoderms, which includes sea urchins and sea cucumbers. Their strange body plans have long puzzled biologists. Most animals, including humans, have a distinct head end and tail end, with a line of symmetry running down the middle of their body, dividing it into two mirror-image halves. Animals with this two-sided symmetry are called bilaterians.
Echinoderms, on the other hand, have five lines of symmetry radiating from a central point and no physically obvious head or tail. Yet they are closely related to animals like us and evolved from a bilaterian ancestor. Even their larvae are bilaterally symmetrical, but radically reorganise their bodies as they metamorphose into adults.
Laurent Formery at Stanford University says, “The morphology cannot tell you anything, almost.” He and his colleagues decided to look at a set of genes known to direct the head-to-tail organisation of all bilaterians. In these animals, the genes are turned on, or expressed, in stripes in the outer layer of the developing embryo. The genes that are expressed in each stripe define which point on the head-to-tail axis it will become.
The team wanted to see if the gene expression patterns would reveal a “molecular anatomy” in starfish. To their surprise, the genes that determine the head end in bilaterians were expressed in a line running down the middle of each arm on the underside of a starfish. The next “head - most” genes were expressed on either side of this line. Even more strangely, the genes normally expressed in the trunk of bilaterians were missing in the outer layer of the starfish. This suggests that starfish have jettisoned their trunk regions and freed up the outer layer to evolve in new directions.
The findings show that “the body of an echinoderm, at least in terms of the external body surface, is essentially a head walking about on its lips on the seafloor,” says Thurston Lacalli at the University of Victoria in Canada.
What conclusion have scientists reached about starfish
A. Starfish have a clearly defined head and tail.
B. The whole starfish can be seen as its head.
C. Starfish evolved from a non - bilaterian ancestor.
D. Starfish larvae have no symmetry.
What is the difference between echinoderms and bilaterians
A. Echinoderms have a line of symmetry running down the middle of their body.
B. Bilaterians have five lines of symmetry radiating from a central point.
C. Echinoderms don't have an obvious head or tail physically.
D. Bilaterians' genes are expressed in a more complex way.
What did Formery's team find in their research on starfish
A. The gene expression patterns in starfish are the same as those in bilaterians.
B. The genes determining the head end in bilaterians were not expressed in starfish.
C. Starfish have developed new gene expression patterns in their trunk regions.
D. Some genes normally found in the trunk of bilaterians were absent in starfish's outer layer.
What can we infer from Thurston Lacalli's words
A. Starfish's body structure is unique in the animal kingdom.
B. Starfish use their heads to move on the seafloor.
C. Starfish have a more advanced body structure than bilaterians.
D. Starfish's body surface has a special function for protection.
答案
B。根据文章第一段 “Scientists trying to determine where a starfish's head is have come to a startling conclusion: it is effectively the whole animal.” 可知，科学家得出的结论是整个海星都可以看作是它的头部，B 选项正确。A 选项与原文中 “Echinoderms... have no physically obvious head or tail” 相悖；从 “Yet they are closely related to animals like us and evolved from a bilaterian ancestor.” 可知海星是从两侧对称动物祖先进化而来，C 选项错误；文中提到 “Even their larvae are bilaterally symmetrical”，说明海星幼虫是两侧对称的，D 选项错误。
C。由第二段 “Most animals, including humans, have a distinct head end and tail end... Animals with this two-sided symmetry are called bilaterians.” 以及第三段 “Echinoderms, on the other hand, have five lines of symmetry radiating from a central point and no physically obvious head or tail.” 可知，棘皮动物（海星所属类别）在身体上没有明显的头部或尾部，而两侧对称动物有明显的头尾之分，C 选项正确。A 选项描述的是两侧对称动物的特征；B 选项中五条对称线辐射是棘皮动物的特征；文中未提及两者基因表达的复杂程度比较，D 选项错误。
D。根据倒数第二段 “Even more strangely, the genes normally expressed in the trunk of bilaterians were missing in the outer layer of the starfish.” 可知，在海星的外层中，通常在两侧对称动物躯干中表达的一些基因缺失了，D 选项正确。研究发现海星和两侧对称动物的基因表达模式有差异，A 选项错误；从 “the genes that determine the head end in bilaterians were expressed in a line running down the middle of each arm on the underside of a starfish” 可知两侧对称动物中决定头部的基因在海星中是有表达的，B 选项错误；文中说海星抛弃了躯干区域，并非是在躯干区域形成了新的基因表达模式，C 选项错误。
A。Thurston Lacalli 说 “the body of an echinoderm, at least in terms of the external body surface, is essentially a head walking about on its lips on the seafloor”，结合前文对海星独特身体结构和基因表达的研究，可以推断出海星的身体结构在动物界是独特的，A 选项正确。文中说的是从某种角度上海星的身体就像一个用 “嘴唇” 在海底行走的头部，并非真的用头部移动，B 选项错误；文中没有将海星和两侧对称动物的身体结构进行先进程度的比较，C 选项错误；文中未提及海星身体表面的保护功能，D 选项错误。
Passage 2
Roosters show distinct behaviors when encountering another chicken compared to seeing their own reflection in a mirror. This difference hints that these birds might possess the ability to recognize themselves in a mirror, an important sign of self - awareness.
The traditional mirror self - recognition test, dating back to 1970, involves placing a mark on an animal's body in a spot only visible through its reflection. Researchers then observe if the animal touches or inspects the mark while looking at its mirror image. If it does, it implies that the animal understands the reflection represents its own body. Although few non - human species have passed this test, great apes, dolphins, elephants, and magpies are among them.
Recently, there have been claims that species like penguins, horses, cleaner wrasse fish, and manta rays have passed the test, but these claims are controversial. Sonja Hillemann from the University of Bonn in Germany and her colleagues suspected that many animals have little natural incentive to investigate such marks in the traditional test. So, they adjusted the test to align with the natural behavior of roosters. Roosters typically make loud alarm calls to alert other chickens of nearby predators but remain quiet when alone.
In the laboratory, the team tested 68 roosters one by one in an arena divided by a wire mesh. They placed a rooster on one side, either leaving the other side empty, putting another rooster there, or adding a mirror to the divider for some tests. To simulate a threat, they projected a hawk's silhouette on the arena ceiling.
The results showed that roosters could distinguish between a real rooster and its reflection through vision rather than smell or sound. What's more, since the roosters behaved similarly when alone and when facing their reflection, the researchers suggest that roosters may recognize that the reflection is of themselves. This discovery indicates that self - recognition may be more widespread among animals than previously thought.
What is the significance of the traditional mirror self - recognition test
A. It helps determine if an animal can recognize its friends.
B. It is used to check an animal's ability to react to threats.
C. It can prove whether an animal has self - awareness.
D. It shows an animal's understanding of its own body size.
Why did Sonja Hillemann and her team modify the self - recognition test for roosters
A. Because the traditional test was too difficult for roosters.
B. Because they thought the traditional test didn't suit roosters' natural behavior.
C. Because they wanted to test more animals in a different way.
D. Because roosters couldn't see the marks in the traditional test.
What did the new test on roosters find
A. Roosters can only distinguish reflections through smell.
B. Roosters always act differently when alone and with a reflection.
C. Self - recognition may be more common in animals than we thought.
D. All roosters can definitely recognize themselves in the mirror.
What can we infer from the passage
A. The traditional self - recognition test is completely useless.
B. More species may be able to recognize themselves than we know.
C. Roosters are the only non - ape animals that can pass the new test.
D. Animals' self - recognition ability has nothing to do with their survival.
答案
C。根据文章第二段 “The traditional mirror self - recognition test... If it does, it implies that the animal understands the reflection represents its own body.” 可知，传统的镜子自我认知测试可以证明动物是否有自我意识，C 选项正确。该测试不是用来判断动物是否能识别朋友，A 选项错误；也不是检测动物对威胁的反应能力，B 选项错误；更不是展示动物对自身身体大小的理解，D 选项错误。
B。从文章第四段 “Sonja Hillemann from the University of Bonn in Germany and her colleagues suspected that many animals have little natural incentive to investigate such marks in the traditional test. So, they adjusted the test to align with the natural behavior of roosters.” 可知，Sonja Hillemann 和她的团队修改测试是因为他们认为传统测试不适合公鸡的自然行为，B 选项正确。文中未提及传统测试对公鸡来说太难，A 选项错误；他们修改测试主要是针对公鸡，并非为了用不同方式测试更多动物，C 选项错误；公鸡不能通过传统测试不是因为看不到标记，而是因为该测试不符合它们的自然行为，D 选项错误。
C。依据文章最后一段 “This discovery indicates that self - recognition may be more widespread among animals than previously thought.” 可知，新测试发现自我认知在动物中可能比我们之前认为的更普遍，C 选项正确。文中提到公鸡是通过视觉区分反射和现实，而不是通过嗅觉，A 选项错误；由 “since the roosters behaved similarly when alone and when facing their reflection” 可知 B 选项错误；文章说公鸡可能认识到镜子中的自己，并非肯定都能认识到，D 选项错误。
B。综合全文，尤其是新测试表明公鸡可能有自我认知能力，以及文中提到 “self - recognition may be more widespread among animals than previously thought”，可以推断出可能有更多物种能够自我认知，只是我们还不知道，B 选项正确。文章只是说传统测试对非猿类动物不太合适，并非完全无用，A 选项错误；文中没有表明公鸡是唯一能通过新测试的非猿动物，C 选项错误；动物的自我认知能力可能与它们的生存等方面有关，文章未提及二者毫无关系，D 选项错误。
Passage 3
Vaccines play a crucial role in safeguarding our health, and DNA vaccines are emerging as a promising new option. Michael Le Page states that vaccines containing DNA would be easier to store than mRNA alternatives and should be as effective as conventional vaccines with live viruses.
Medigen, a company, is seeking approval for the first human trials of DNA vaccines designed to produce live viruses in people's bodies. The goal is to combine the potential advantages of DNA vaccines, such as rapid manufacturing and easy storage, with the greater efficacy of vaccines that consist of live weakened viruses. “So instead of giving live virus, we would give a piece of DNA and the body will make the vaccine,” says Peter Pushko at Medigen in Frederick, Maryland.
Medigen has tested two potential vaccines in mice so far, one for chikungunya and one for yellow fever. The DNA vaccines protected the animals when they were later exposed to infection - causing viruses. The company plans to begin human trials next year. “I anticipate we would have the production and storage ease of DNA, but the potency of a live virus,” says Pushko. “As soon as we get the go - ahead from the FDA [US Food and Drug Administration], we will start testing in a phase 1 clinical trial.”
It's also possible for weakened viruses to revert to the dangerous form, which happens with the live polio vaccine, albeit rarely. Many modern vaccines consist of “dead” viruses that can't replicate or of viral proteins, rather than an entire virus, such as the human papillomavirus and hepatitis B vaccines. However, these vaccines typically require repeated doses to produce a strong enough response.
One potential advantage of DNA vaccines over mRNA ones is that the molecule is more stable. DNA vaccines can be kept in a fridge or even at room temperature, rather than needing to be kept frozen like most mRNA vaccines, says Pushko. DNA vaccines coding for live viruses help solve the delivery problem because once a few viruses are made, they start replicating themselves. So people get an effective dose even if relatively few DNA molecules reach the nuclei of cells.
What is special about DNA vaccines according to the passage
A. They are more effective than conventional vaccines.
B. They are the first vaccines to be tested on humans.
C. They are easier to store compared to some other vaccines.
D. They contain live weakened viruses for better protection.
What can we learn about Medigen's DNA vaccines
A. They have already been approved for human trials.
B. They have been tested on humans for chikungunya and yellow fever.
C. They aim to combine advantages of different vaccine types.
D. They can only be stored in a fridge or at room temperature.
Why are many modern vaccines made of “dead” viruses or viral proteins
A. Because they can replicate easily in the human body.
B. Because they are more potent than live virus vaccines.
C. Because they are less likely to revert to a dangerous form.
D. Because they don't require repeated doses.
What is one advantage of DNA vaccines over mRNA vaccines
A. They can make more viral proteins.
B. The DNA molecule is more stable.
C. They can produce a stronger response.
D. They can be made more quickly.
答案
C。根据文章第一段 “vaccines containing DNA would be easier to store than mRNA alternatives and should be as effective as conventional vaccines with live viruses” 可知，与一些其他疫苗（如 mRNA 疫苗）相比，DNA 疫苗更容易储存，C 选项正确。文中说 DNA 疫苗应和传统含活病毒疫苗一样有效，并非更有效，A 选项错误；文中提到 Medigen 正寻求 DNA 疫苗人体试验的批准，并非说它们是首批在人体上测试的疫苗，B 选项错误；DNA 疫苗是通过给人体 DNA 让身体制造疫苗，不是本身含有减毒活病毒，D 选项错误。
C。从第二段 “The goal is to combine the potential advantages of DNA vaccines, such as rapid manufacturing and easy storage, with the greater efficacy of vaccines that consist of live weakened viruses.” 可知，Medigen 的 DNA 疫苗旨在结合不同类型疫苗的优势，C 选项正确。文中说公司正寻求人体试验批准，还未获批，A 选项错误；目前只在老鼠身上进行了试验，还未在人体上测试，B 选项错误；最后一段提到 DNA 疫苗可以在冰箱甚至室温下保存，但不是只能在这两种条件下保存，D 选项错误。
C。根据第四段 “It's also possible for weakened viruses to revert to the dangerous form, which happens with the live polio vaccine, albeit rarely. Many modern vaccines consist of ‘dead’ viruses that can't replicate or of viral proteins...” 可知，许多现代疫苗由 “死” 病毒或病毒蛋白制成是因为弱化病毒有可能恢复到危险形式，而这些疫苗能避免这种情况，C 选项正确。这些疫苗中的 “死” 病毒不能复制，A 选项错误；文中未提及它们比活病毒疫苗效力更强，B 选项错误；第四段提到这些疫苗通常需要重复接种以产生足够强的反应，D 选项错误。
B。依据最后一段 “One potential advantage of DNA vaccines over mRNA ones is that the molecule is more stable.” 可知，DNA 疫苗相对 mRNA 疫苗的一个优势是其分子更稳定，B 选项正确。文中未提及 DNA 疫苗能制造更多病毒蛋白，A 选项错误；没有对比两者产生的反应强弱，C 选项错误；也没有提到制作速度的问题，D 选项错误。
