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 is the best version of the underlined portion of sentence 6 (reproduced below)? More recent discoveries of sauropod fossils in locations around the world have confirmed that these resilient animals, did indeed walk the earth for millions of years.
- A. (as it is now)
- B. that, these resilient animals
- C. that these resilient animals.
- D. that these resilient animals
Correct Answer & Rationale
Correct Answer: D
Option D is the best choice as it eliminates unnecessary punctuation, creating a smooth and grammatically correct sentence. The phrase "that these resilient animals" flows naturally and maintains clarity. Option A retains the comma, which incorrectly separates the subject from the verb, leading to a fragmented structure. Option B includes an unnecessary comma after "that," disrupting the sentence's flow. Option C, while similar to D, incorrectly ends with a period, making it incomplete and affecting the overall coherence of the sentence.
Option D is the best choice as it eliminates unnecessary punctuation, creating a smooth and grammatically correct sentence. The phrase "that these resilient animals" flows naturally and maintains clarity. Option A retains the comma, which incorrectly separates the subject from the verb, leading to a fragmented structure. Option B includes an unnecessary comma after "that," disrupting the sentence's flow. Option C, while similar to D, incorrectly ends with a period, making it incomplete and affecting the overall coherence of the sentence.
In context, which word or phrase is best to insert at the beginning of sentence 11? Sentence 11: He spent most of his time writing poems in Spanish instead of studying English.
- A. In addition.
- B. For example.
- C. However.
- D. Indeed.
Correct Answer & Rationale
Correct Answer: C
The choice of "However" effectively contrasts the subject's choice to write poems in Spanish with the expectation that he should be studying English. This juxtaposition highlights a shift in focus, emphasizing the divergence from expected behavior. Option A, "In addition," suggests continuity rather than contrast, which does not align with the sentence's intent. Option B, "For example," implies that the sentence will provide an instance, which is not the case here. Option D, "Indeed," reinforces a statement rather than introducing a contrasting idea, making it unsuitable for the context.
The choice of "However" effectively contrasts the subject's choice to write poems in Spanish with the expectation that he should be studying English. This juxtaposition highlights a shift in focus, emphasizing the divergence from expected behavior. Option A, "In addition," suggests continuity rather than contrast, which does not align with the sentence's intent. Option B, "For example," implies that the sentence will provide an instance, which is not the case here. Option D, "Indeed," reinforces a statement rather than introducing a contrasting idea, making it unsuitable for the context.
Which sentence should be deleted because it contains irrelevant information?
- A. Sentence 6
- B. Sentence 7
- C. Sentence 9
- D. Sentence 14
Correct Answer & Rationale
Correct Answer: C
Sentence 9 introduces information that does not directly support the main argument or theme of the passage, making it irrelevant to the central discussion. In contrast, Sentence 6 provides context, Sentence 7 offers a critical example, and Sentence 14 concludes the argument effectively. Each of these sentences contributes meaningfully to the overall coherence and purpose of the text. Removing Sentence 9 enhances clarity by eliminating distractions, allowing the reader to focus on the essential points being made.
Sentence 9 introduces information that does not directly support the main argument or theme of the passage, making it irrelevant to the central discussion. In contrast, Sentence 6 provides context, Sentence 7 offers a critical example, and Sentence 14 concludes the argument effectively. Each of these sentences contributes meaningfully to the overall coherence and purpose of the text. Removing Sentence 9 enhances clarity by eliminating distractions, allowing the reader to focus on the essential points being made.
The writer is considering adding the following sentence to the end of the fourth paragraph: 'Surprisingly, according to The Economist, there were 1.6 million commercial farms in Brazil in 2010.' Should the writer make this addition here?
- A. Yes, because it emphasizes the paragraph's focus on the economic power of large farms.
- B. Yes, because it uses concrete data to provide context about local farms and commercial farms.
- C. No, because it is unrelated to the economic challenges small farms may face.
- D. No, because it fails to show a clear connection to the paragraph's focus on supporting local farms.
Correct Answer & Rationale
Correct Answer: B
Adding the sentence enhances the paragraph by providing concrete data, which helps contextualize the discussion about local and commercial farms. It bridges the gap between the economic landscape and the realities faced by different types of farms, enriching the reader's understanding. Option A misinterprets the focus; while large farms are mentioned, the emphasis is on the economic challenges faced by smaller farms. Option C incorrectly suggests that the data is unrelated; understanding the number of commercial farms is essential to discussing the economic landscape. Option D overlooks that the data can indeed support a broader discussion about local farms by contrasting them with commercial operations.
Adding the sentence enhances the paragraph by providing concrete data, which helps contextualize the discussion about local and commercial farms. It bridges the gap between the economic landscape and the realities faced by different types of farms, enriching the reader's understanding. Option A misinterprets the focus; while large farms are mentioned, the emphasis is on the economic challenges faced by smaller farms. Option C incorrectly suggests that the data is unrelated; understanding the number of commercial farms is essential to discussing the economic landscape. Option D overlooks that the data can indeed support a broader discussion about local farms by contrasting them with commercial operations.