Resin is a plant secretion that hardens when exposed to air; fossilized resin is called amber. Although Pliny in the...
GMAT Reading Comprehension : (RC) Questions
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Resin is a plant secretion that hardens when exposed to air; fossilized resin is called amber. Although Pliny in the first century recognized that amber was produced from "marrow discharged by trees," amber has been widely misunderstood to be a semiprecious gem and has even been described in mineralogy textbooks. Confusion also persists surrounding the term "resin," which was defined before rigorous chemical analyses were available. Resin is often confused with gum, a substance produced in plants in response to bacterial infections, and with sap, an aqueous solution transported through certain plant tissues. Resin differs from both gum and sap in that scientists have not determined a physiological function for resin.
In the 1950s, entomologists posited that resin may function to repel or attract insects. Fraenkel conjectured that plants initially produced resin in nonspecific chemical responses to insect attack and that, over time, plants evolved that produced resin with specific repellent effects. But some insect species, he noted, might overcome the repellent effects, actually becoming attracted to the resin. This might induce the insects to feed on those plants or aid them in securing a breeding site. Later researchers suggested that resin mediates the complex interdependence, or "coevolution," of plants and insects over time. Such ideas led to the development of the specialized discipline of chemical ecology, which is concerned with the role of plant chemicals in interactions with other organisms and with the evolution and ecology of plant antiherbivore chemistry (plants' chemical defenses against attack by herbivores such as insects).
Ques. 1/4
According to the passage, which of the following is true of plant antiherbivore chemistry?
Solution
1. Passage Analysis:
Progressive Passage Analysis
| Text from Passage | Analysis |
|---|---|
| Resin is a plant secretion that hardens when exposed to air; fossilized resin is called amber. | What it says: Plants make a substance called resin that gets hard when it touches air. Old, fossilized resin becomes amber. What it does: Defines two key terms (resin and amber) and establishes their basic relationship Source/Type: Factual definition Connection to Previous Sentences: This is our starting point - no previous information to connect to Visualization: Think of tree sap oozing out and hardening into a solid chunk, then imagine that chunk buried for millions of years becoming amber What We Know So Far: Resin = plant secretion that hardens; Amber = fossilized resin What We Don't Know Yet: Why plants make resin, how it's different from other plant substances, what scientists think about it Reading Strategy Insight: Clean, simple definitions - build confidence here! |
| Although Pliny in the first century recognized that amber was produced from "marrow discharged by trees," amber has been widely misunderstood to be a semiprecious gem and has even been described in mineralogy textbooks. | What it says: An ancient Roman (Pliny) correctly identified amber as coming from trees, but most people wrongly think amber is a gem like a ruby or emerald. What it does: Shows historical confusion about amber's true nature Source/Type: Historical fact + widespread misconception Connection to Previous Sentences: This builds on sentence 1's definition of amber by showing that despite early correct knowledge, people got confused about what amber really is Visualization: Picture amber jewelry in a gem store next to diamonds and emeralds - people think it belongs there, but it's actually hardened tree resin Reading Strategy Insight: This reinforces our first sentence - amber IS from trees (Pliny was right!), but adds that people commonly misunderstand this |
| Confusion also persists surrounding the term "resin," which was defined before rigorous chemical analyses were available. | What it says: People are also confused about what resin is because the word was defined before scientists had good tools to study it chemically. What it does: Extends the "confusion" theme from amber to resin itself Source/Type: Author's explanation of historical/scientific context Connection to Previous Sentences: This continues the confusion theme from sentence 2. Pattern emerging: Both amber AND resin are misunderstood Visualization: Imagine scientists 200 years ago trying to define "resin" without modern chemistry equipment - like trying to describe a car engine without being able to see under the hood Reading Strategy Insight: Feel confident here - you're seeing a clear pattern of "things are confusing but we're going to clarify them" |
| Resin is often confused with gum, a substance produced in plants in response to bacterial infections, and with sap, an aqueous solution transported through certain plant tissues. | What it says: People mix up resin with two other plant substances: gum (which plants make when bacteria attack them) and sap (which is basically plant blood that carries nutrients). What it does: Gives specific examples of what resin gets confused with and briefly explains what those things actually are Source/Type: Factual clarification Connection to Previous Sentences: This provides concrete examples of the "confusion" mentioned in sentence 3. The author is helping us by showing exactly what the confusion looks like Visualization: Three buckets: Bucket 1 (resin) = mystery substance we're learning about; Bucket 2 (gum) = plant's infection response; Bucket 3 (sap) = plant's transport system Reading Strategy Insight: This is simplification, not complication! The author is clarifying by showing us what resin is NOT |
| Resin differs from both gum and sap in that scientists have not determined a physiological function for resin. | What it says: Unlike gum and sap (which have clear purposes), scientists don't know why plants make resin. What it does: Establishes the key mystery about resin that drives the rest of the passage Source/Type: Scientific knowledge gap Connection to Previous Sentences: This directly builds on sentence 4 by explaining the crucial difference between resin and the other substances. This is our central question: What is resin FOR? Visualization: Gum = plant's medicine cabinet (clear purpose); Sap = plant's bloodstream (clear purpose); Resin = mystery substance with unknown purpose What We Know So Far: Resin hardens when exposed to air, becomes amber when fossilized, gets confused with gum and sap, but unlike those substances has no known purpose What We Don't Know Yet: What scientists think resin might be for Reading Strategy Insight: Perfect setup sentence - now we know exactly what question the passage will try to answer |
| In the 1950s, entomologists posited that resin may function to repel or attract insects. | What it says: In the 1950s, bug scientists guessed that resin might work to either keep insects away or draw them in. What it does: Introduces the first scientific theory about resin's purpose Source/Type: Scientific hypothesis/theory Connection to Previous Sentences: This directly answers the mystery set up in sentence 5. We're moving from "unknown purpose" to "here's what scientists think the purpose might be" Visualization: Picture resin acting like either insect repellent (bug spray) or like a flower attracting bees - scientists weren't sure which Reading Strategy Insight: This is progress! We're getting our first answer to the mystery |
| Fraenkel conjectured that plants initially produced resin in nonspecific chemical responses to insect attack and that, over time, plants evolved that produced resin with specific repellent effects. | What it says: A scientist named Fraenkel thought that plants first made resin as a general chemical reaction to bug attacks, then eventually evolved to make resin that specifically repelled certain insects. What it does: Provides a specific scientist's detailed theory about how resin's insect-repelling function developed over time Source/Type: Individual researcher's theory (Fraenkel's conjecture) Connection to Previous Sentences: This elaborates on the "repel insects" part of sentence 6, giving us a specific evolutionary story about how this repelling function might have developed Visualization: Timeline: Step 1 = Plants under bug attack make resin randomly; Step 2 = Over millions of years, plants that made better anti-bug resin survived better; Step 3 = Modern plants with targeted insect repellent Reading Strategy Insight: This adds detail to our previous sentence rather than introducing a completely new idea |
| But some insect species, he noted, might overcome the repellent effects, actually becoming attracted to the resin. | What it says: Fraenkel also said that some bugs might get used to the repellent and actually start liking the resin. What it does: Shows how the repellent function could flip to become an attractant Source/Type: Continuation of Fraenkel's theory Connection to Previous Sentences: This connects back to sentence 6 which mentioned resin could "repel OR attract" insects. Now we see how the same substance could do both! Visualization: Imagine bugs initially running away from resin, then over time some bugs developing a taste for it - like how some people love extremely spicy food that repels others Reading Strategy Insight: This explains the "or attract" part from sentence 6 - we're getting a complete picture, not new confusion |
| This might induce the insects to feed on those plants or aid them in securing a breeding site. | What it says: If bugs become attracted to resin, they might eat those plants or use them as places to reproduce. What it does: Explains what would happen if insects became attracted to resin instead of repelled Source/Type: Logical consequence of Fraenkel's theory Connection to Previous Sentences: This directly follows from sentence 8, explaining the practical results of insects being attracted to resin Visualization: Picture insects eating resin-producing plants and laying eggs on them because they're drawn to the resin Reading Strategy Insight: Simple cause-and-effect - if bugs like resin, then they'll eat the plants and breed on them |
| Later researchers suggested that resin mediates the complex interdependence, or "coevolution," of plants and insects over time. | What it says: Scientists who came after Fraenkel said that resin helps manage the complicated back-and-forth relationship between plants and insects as they evolve together. What it does: Introduces a broader, more sophisticated theory that builds on earlier ideas Source/Type: Later researchers' expanded theory Connection to Previous Sentences: This takes all the repelling/attracting ideas from sentences 6-9 and puts them into a bigger framework. This is a summary and expansion, not a contradiction Visualization: Think of an evolutionary arms race: plants develop better repellent → bugs adapt to overcome it → plants develop new strategies → bugs counter-adapt, with resin playing a key role in this back-and-forth Reading Strategy Insight: "Coevolution" is just a fancy term for the back-and-forth process we've been learning about |
| Such ideas led to the development of the specialized discipline of chemical ecology, which is concerned with the role of plant chemicals in interactions with other organisms and with the evolution and ecology of plant antiherbivore chemistry (plants' chemical defenses against attack by herbivores such as insects). | What it says: These theories about resin and plant-insect relationships became so important that scientists created a whole new field called chemical ecology to study how plant chemicals interact with other living things and how plants' chemical defenses evolve. What it does: Shows the broader impact and importance of the resin research Source/Type: Historical consequence/field development Connection to Previous Sentences: This shows how all the theories we've been learning about (from sentences 6-10) were significant enough to spawn an entire scientific discipline. This reinforces that the resin story is important and well-established Visualization: Picture the resin research growing from a few scientists' questions into university departments, textbooks, and specialized journals What We Know So Far: Resin is a plant secretion that becomes amber, was historically misunderstood, has unknown purpose, but scientists theorize it evolved to repel/attract insects in a coevolutionary dance, leading to an entire field of study Reading Strategy Insight: This is a "importance" signal - the passage is showing us why this topic matters by explaining its impact on science |
2. Passage Summary:
Author's Purpose:
To explain the historical confusion surrounding resin and trace how scientific understanding of its function has evolved from mystery to the development of an entire field of study.
Summary of Passage Structure:
In this passage, the author walks us through the journey from confusion to scientific understanding about resin:
- First, the author defines what resin and amber are, then shows how both have been historically misunderstood despite early correct knowledge
- Next, the author explains specific confusions about resin by contrasting it with gum and sap, highlighting that unlike these substances, resin has no known biological purpose
- Then, the author presents scientific theories that emerged in the 1950s about resin's possible function in repelling or attracting insects, including detailed explanations of how this might work evolutionarily
- Finally, the author shows how these theories evolved into broader concepts of coevolution between plants and insects, ultimately leading to the creation of an entire scientific field called chemical ecology
Main Point:
What started as a mysterious plant substance with no known purpose has become the foundation for understanding how plants and insects evolve together, spawning an entire scientific discipline that studies plant chemical defenses.
3. Question Analysis:This question asks us to identify what is true about plant antiherbivore chemistry according to the passage. "Antiherbivore chemistry" refers to the chemical defenses plants use against herbivores (plant-eating animals like insects).
Connecting to Our Passage Analysis:- Our passage analysis shows that resin is theorized to function as either a repellent or attractant to insects
- Fraenkel's theory explained how plants evolved specific repellent effects over time
- The passage describes how some insects might "overcome the repellent effects, actually becoming attracted to the resin"
- This attraction could "induce the insects to feed on those plants"
- The final sentence explicitly defines "plant antiherbivore chemistry" as "plants' chemical defenses against attack by herbivores such as insects"
From our passage analysis, we know that changes in plant chemistry (specifically resin production) directly affect insect behavior - either repelling them or attracting them, which then influences their feeding patterns. The passage traces an evolutionary story where plant chemical defenses and insect responses evolve together. This suggests that modifications in a plant's chemical defenses would logically affect how insects interact with and feed on those plants.
Answer Choices Explained
A
Changes in a plant's antiherbivore chemistry may affect insect feeding behavior.
Why It's Right:
- The passage explicitly describes how plants evolved "specific repellent effects" that would deter insect feeding
- It also explains how insects might "overcome the repellent effects" and become attracted, leading them to "feed on those plants"
- This directly shows that changes in antiherbivore chemistry affect insect feeding behavior
- The coevolution concept reinforces that plant chemistry changes drive corresponding changes in insect behavior
Key Evidence: "But some insect species, he noted, might overcome the repellent effects, actually becoming attracted to the resin. This might induce the insects to feed on those plants"
B
A plant's repellent effects often involve interactions between gum and resin.
Why It's Wrong:
- The passage clearly distinguishes resin from gum, stating they serve different functions
- Gum is produced "in response to bacterial infections," not for repelling herbivores
- No interaction between gum and resin is mentioned in the context of repellent effects
Common Student Mistakes:
- Confusing the three plant substances mentioned? → Remember: gum = bacterial response, sap = transport, resin = unknown function (possibly insect-related)
- Thinking all plant chemicals work together? → The passage emphasizes how these substances have distinct, separate functions
C
A plant's antiherbivore responses assist in combating bacterial infections.
Why It's Wrong:
- This confuses gum with antiherbivore chemistry
- Gum is specifically produced "in response to bacterial infections," not herbivore attacks
- Antiherbivore chemistry deals with insect defense, not bacterial infections
Common Student Mistakes:
- Mixing up plant defense systems? → Bacterial defense ≠ herbivore defense; plants have different chemicals for different threats
- Assuming all plant responses are the same? → The passage specifically differentiates between responses to bacteria versus insects
D
Plant antiherbivore chemistry plays only a minor role in the coevolution of plants and insects.
Why It's Wrong:
- This contradicts the passage's emphasis on the importance of plant-insect coevolution
- The development of an entire scientific field (chemical ecology) shows antiherbivore chemistry plays a major role
- The passage describes "complex interdependence" between plants and insects, indicating significant importance
Common Student Mistakes:
- Missing the significance signals in the passage? → When an entire scientific discipline develops from studying something, it indicates major importance
- Focusing only on uncertainty rather than developed theories? → While resin's function was initially unknown, substantial theories have emerged
E
Researchers first studied repellent effects in plants beginning in the 1950s.
Why It's Wrong:
- The passage states research on repellent effects began "in the 1950s," but this was specifically about resin
- This doesn't mean that ALL research on plant repellent effects began then
- The question asks about plant antiherbivore chemistry generally, not just resin research
Common Student Mistakes:
- Assuming the specific timeline applies broadly? → The 1950s date refers specifically to resin theories, not all antiherbivore research
- Confusing "first studied" with "first theorized about resin"? → Plants' defensive chemistry was likely studied before the 1950s in other contexts
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