Poison frogs become poisonous by isolating chemicals from their food and storing them in their skin. One such compound, epibatidine, is a stronger painkiller than morphine, but has not been tested in humans because even low doses are deadly to rodents. But for the frogs themselves, this powerful neurotoxin is totally impotent. According to a study published in Science, several groups of epibatidine-bearing frogs have independently evolved amino acid changes in the toxin's target, the nicotinic acetylcholine receptor. These modifications allow the amphibians to escape self-toxicity.
The main idea of the passage is that some types of poison frogs:
- A. have developed the capacity to protect themselves from the poison they carry in their skin
- B. could eventually produce a natural pain relief option for people who suffer from headaches
- C. combine chemicals from their food to create a toxic substance that keeps them safe from predators
- D. can be grouped based on the changes they've made to their nicotinic acetylcholine receptors
Correct Answer & Rationale
Correct Answer: A
Option A highlights the unique adaptation of certain poison frogs, emphasizing their ability to protect themselves from their own toxins. This reflects a key aspect of their survival strategy. Option B, while interesting, suggests a potential human application of frog toxins that is not the main focus of the passage. Option C inaccurately attributes the creation of toxins solely to food sources, overlooking the frogs' inherent toxic traits. Option D focuses on a specific biological mechanism that, while relevant, does not encapsulate the broader theme of self-protection central to the passage.
Option A highlights the unique adaptation of certain poison frogs, emphasizing their ability to protect themselves from their own toxins. This reflects a key aspect of their survival strategy. Option B, while interesting, suggests a potential human application of frog toxins that is not the main focus of the passage. Option C inaccurately attributes the creation of toxins solely to food sources, overlooking the frogs' inherent toxic traits. Option D focuses on a specific biological mechanism that, while relevant, does not encapsulate the broader theme of self-protection central to the passage.
Other Related Questions
Which choice best replaces the underlined portion of sentence 2 (reproduced below)? The pictorial quilts created by a former slave named Harriet Powers, in addition, were remarkable for their bold storytelling techniques and their unique subject matter.
- A. by contrast,
- B. for example,
- C. it so happens,
- D. moreover,
Correct Answer & Rationale
Correct Answer: D
The phrase "in addition" suggests that the following information will build on or add to the previous point. Option D, "moreover," effectively conveys this continuation of thought, emphasizing that Harriet Powers' quilts not only have a historical significance but also possess remarkable qualities. Option A, "by contrast," implies a comparison that highlights differences, which does not fit the context. Option B, "for example," indicates a specific illustration rather than adding information. Option C, "it so happens," is too vague and does not establish a clear connection to the preceding statement. Thus, "moreover" is the most suitable choice for enhancing the sentence's cohesiveness.
The phrase "in addition" suggests that the following information will build on or add to the previous point. Option D, "moreover," effectively conveys this continuation of thought, emphasizing that Harriet Powers' quilts not only have a historical significance but also possess remarkable qualities. Option A, "by contrast," implies a comparison that highlights differences, which does not fit the context. Option B, "for example," indicates a specific illustration rather than adding information. Option C, "it so happens," is too vague and does not establish a clear connection to the preceding statement. Thus, "moreover" is the most suitable choice for enhancing the sentence's cohesiveness.
Which is the best way to revise and combine sentences 3 and 4 (reproduced below)? Lorca was the oldest son of a wealthy landowner. He studied literature and law at the University of Granada before turning to writing full-time.
- A. Lorca was the oldest son of a wealthy landowner, studied literature and law at the University of Granada before turning to writing full-time.
- B. The oldest son of a wealthy landowner, Lorca studied literature and law at the University of Granada before turning to writing full-time.
- C. Lorca, the oldest son of a wealthy landowner, studying literature and law at the University of Granada before turning to writing full-time.
- D. The oldest son of a wealthy landowner who studied literature and law at the University of Granada, Lorca then turning to writing full-time.
Correct Answer & Rationale
Correct Answer: B
Option B effectively combines the two sentences by placing the subject, Lorca, at the beginning and clearly linking his identity to his actions. This structure maintains clarity and coherence, allowing readers to easily follow the progression of ideas. Option A lacks a conjunction, resulting in a sentence fragment that does not convey a complete thought. Option C incorrectly uses "studying," which creates a grammatical error by failing to connect the clauses properly. Option D introduces unnecessary complexity with "who studied," and the phrase "Lorca then turning" is awkward and grammatically incorrect. Thus, option B stands out as the most coherent and grammatically sound choice.
Option B effectively combines the two sentences by placing the subject, Lorca, at the beginning and clearly linking his identity to his actions. This structure maintains clarity and coherence, allowing readers to easily follow the progression of ideas. Option A lacks a conjunction, resulting in a sentence fragment that does not convey a complete thought. Option C incorrectly uses "studying," which creates a grammatical error by failing to connect the clauses properly. Option D introduces unnecessary complexity with "who studied," and the phrase "Lorca then turning" is awkward and grammatically incorrect. Thus, option B stands out as the most coherent and grammatically sound choice.
Which choice best replaces the underlined portion of sentence 1 (reproduced below)? When selecting her ingredients, a chef has a seemingly small-but nonetheless consequential choice-she can patronize a conventional grocery store, or she can turn to a nearby farm.
- A. small but nonetheless consequential choice,
- B. small but nonetheless consequential choice:
- C. small-but nonetheless consequential choice;
- D. small but nonetheless, consequential choice,
Correct Answer & Rationale
Correct Answer: B
Option B effectively uses a colon to introduce the two alternatives, enhancing clarity. The colon indicates that what follows elaborates on the choice being discussed. Option A lacks proper punctuation to separate the phrases, making it less clear. Option C incorrectly uses a semicolon, which is inappropriate here as it suggests a stronger separation between clauses than intended. Option D misplaces the comma, creating an unnecessary pause that disrupts the flow of the sentence. Overall, option B best maintains the sentence's coherence while clearly presenting the alternatives.
Option B effectively uses a colon to introduce the two alternatives, enhancing clarity. The colon indicates that what follows elaborates on the choice being discussed. Option A lacks proper punctuation to separate the phrases, making it less clear. Option C incorrectly uses a semicolon, which is inappropriate here as it suggests a stronger separation between clauses than intended. Option D misplaces the comma, creating an unnecessary pause that disrupts the flow of the sentence. Overall, option B best maintains the sentence's coherence while clearly presenting the alternatives.
The passage indicates that ancient astronomers were 'baffled' because:
- A. Their observations disproved the poetic tales of early cosmologies
- B. They lacked the mathematical sophistication needed to calculate astronomical distances
- C. Their theories of planetary movements were more complicated than the movements themselves
- D. They could not reliably predict observable celestial phenomena
Correct Answer & Rationale
Correct Answer: D
Ancient astronomers were 'baffled' primarily because they struggled to reliably predict observable celestial phenomena. This unpredictability challenged their understanding and led to confusion in their astronomical models. Option A is incorrect as it implies a conflict with poetic tales, which was not the primary concern of astronomers. Option B misrepresents the issue; while mathematical sophistication was limited, the core problem was not solely about calculations. Option C inaccurately suggests that their theories were overly complex; rather, the issue lay in their inability to accurately forecast celestial events, which is the essence of their bafflement.
Ancient astronomers were 'baffled' primarily because they struggled to reliably predict observable celestial phenomena. This unpredictability challenged their understanding and led to confusion in their astronomical models. Option A is incorrect as it implies a conflict with poetic tales, which was not the primary concern of astronomers. Option B misrepresents the issue; while mathematical sophistication was limited, the core problem was not solely about calculations. Option C inaccurately suggests that their theories were overly complex; rather, the issue lay in their inability to accurately forecast celestial events, which is the essence of their bafflement.