Time and again, whenever a population of [Mexican tetra fish] was swept into a cave and survived long enough for natural selection to have its way, the caves adapted. ”But it’s not that they have been losing their vision,” as one of the authors of the study explains. ”Studies have found that cave-dwelling fish can detect lower levels of amino acids than surface fish can. They have also more tastebuds and a higher density of sensitive cells alongside their bodies that let them sense water pressure and flow . . .”
Killing the processes that support the formation of the eye is quite literally what happens. Just like non-cave-dwelling members of the species, all cavefish embryos start making eyes. But after a few hours, cells in the developing eye get tiny until the entire structure has disappeared. (Developmental biologist Melody Riddle thinks this apparent inefficiency may be unavoidable: ”The development of the brain and the eye are completely intertwined—so when eyes disappear, it impacts the entire biology of the animal. It’s hard to tell exactly how they happen together,” she says. That means the last step in survival for eye-less animals may be to start making an eye and then get rid of it. . . .
It’s easy to see why cavefish would be at a disadvantage if they were to maintain excessive tissues they aren’t using. Since relatively little lives or grows in their caves, the fish are likely surviving on a meager diet of mostly bat feces and organic waste that washes in during the rainy season. Researchers keeping cavefish in labs have discovered that cavefish are exquisitely adapted to absorbing and using nutrients. . . .
Cells can be toxic for tissues, [evolutionary physiologist Nicolas] Rohner explains, so they are stored in fat cells. ”But when these cells get too big, they can burst, which is why we often see chronic inflammation in humans and other animals that have stored a lot of fat in their tissues.” Yet a 2020 study by Riddle, Rohner and their colleagues revealed that even very well-fed cavefish had fewer signs of inflammation in their fat tissues than surface fish do. Even in their sparse cave conditions, wild cavefish can sometimes get very fat, says Riddle. This is presumably because, whenever food piles up in the cave, the fish eat as much of it as possible, since there might not be enough for a long time to come. Intriguingly, Riddle says, their fat is usually bright yellow, because of high levels of carotenoids, the substance in the carrots that your grandmother used to tell you were good for your...eyes. ”The first thing that came to our mind, of course, was that they were accumulating these compounds because they don’t have eyes,” says Riddle. In this species, such ideas can be tested: Scientists can cross surface fish (with eyes) and cavefish (without eyes) and look at what their offspring are like. When that’s done, Riddle says, researchers see no link between eye presence or size and the accumulation of carotenoids. Some eyeless cavefish had fat that was completely white, indicating lower carotenoid levels. Instead, Riddle thinks these carotenoids may be another adaptation to suppress inflammation, which might be important in the wild, as cavefish are likely eating whenever food arrives.
All of the following statements from the passage describe adaptation in Mexican tetra cavefish EXCEPT:
Show Hint
- Since relatively little lives or grows in their caves, the fish are likely surviving on a meager diet of mostly bat feces and organic waste that washes in during the rainy season.
- Even in their sparse cave conditions, wild cavefish can sometimes get very fat, says Riddle.
- It’s easy to see why cavefish would be at a disadvantage if they were to maintain excessive tissues they aren’t using.
- But when these cells get too big, they can burst, which is why we often see chronic inflammation in humans and other animals that have stored a lot of fat in their tissues.
The Correct Option is D
Solution and Explanation
The passage discusses the adaptation of Mexican tetra cavefish to their environment. It highlights how their tissues, particularly fat cells, adapt to limited food resources in the cave system.
Step 2: Analyzing the Options:
- (1) This statement is consistent with the passage’s description of the fish surviving on meager resources in their cave habitat.
- (2) This option also aligns with the passage, as it discusses cavefish getting fat even in sparse conditions.
- (3) This statement describes a logical adaptation of cavefish, which avoids retaining tissues not useful in their environment.
- (4) This statement, while describing a common biological phenomenon, does not directly relate to the adaptation of Mexican tetra cavefish in the passage.
Step 3: Conclusion:
Option (4) is the exception because it relates to a general biological fact rather than a specific adaptation of Mexican tetra cavefish.
On the basis of the information in the passage, what is the most likely function of carotenoids in Mexican tetra cavefish?
Show Hint
- To act as a substitute for eyes.
- To control inflammation from the bursting of fat cells.
- To render bright yellow colour to the cavefish.
- To help the fat cells store nutrients.
The Correct Option is B
Solution and Explanation
The passage suggests that carotenoids play a role in preventing inflammation in the fat cells of the Mexican tetra cavefish. This is important as the fat cells can burst, leading to inflammation.
Step 2: Analyzing the Options:
- (1) This option is not supported by the passage, as carotenoids are not described as a substitute for eyes.
- (2) This option aligns with the passage, which explains how carotenoids help control inflammation from the bursting of fat cells.
- (3) While carotenoids are responsible for the yellow color, this is not the primary function described in the passage.
- (4) This option is not supported by the passage, as carotenoids are not described as helping fat cells store nutrients.
Step 3: Conclusion:
Option (2) best explains the likely function of carotenoids in Mexican tetra cavefish, based on the passage.
Which one of the following results for the cross between surface fish (with eyes) and cavefish (without eyes) would invalidate Riddle’s inference from the experiment?
Show Hint
- Some offspring with eyes had white fat.
- Only eyeless offspring had yellow fat.
- Some offspring with eyes had yellow fat.
- Some eyeless offspring had white fat.
The Correct Option is B
Solution and Explanation
Riddle’s inference suggests that the accumulation of yellow fat in cavefish is related to the absence of eyes. The cross between surface and cavefish is meant to test this hypothesis.
Step 2: Analyzing the Options:
- (1) This result would not invalidate the inference, as it still shows the expected outcome of yellow fat in eyeless fish.
- (2) This result would invalidate the inference, as it shows yellow fat in only eyeless offspring, which does not support the idea that yellow fat is linked to the absence of eyes.
- (3) This result supports the inference by showing that some offspring with eyes have yellow fat, as expected.
- (4) This result is consistent with the hypothesis, showing yellow fat in eyeless offspring.
Step 3: Conclusion:
Option (2) would invalidate Riddle’s inference because it shows that only eyeless offspring had yellow fat.
Which one of the following best explains why the “apparent inefficiency” is “unavoidable”?
Show Hint
- The lack of light in the caves kills the eye cells in the developing Mexican tetra cavefish embryo.
- The inefficiency resulting from eyelessness is compensated by enhancements like more tastebuds in Mexican tetra cavefish.
- The caves have poor and inconsistent availability of food and nutrition for Mexican tetra cavefish.
- Mexican tetra cavefish are similar to non-cave-dwelling variants in their early stages of development.
The Correct Option is D
Solution and Explanation
The passage discusses how the inefficiency of Mexican tetra cavefish development is due to the loss of eye cells and their initial similarity to non-cave-dwelling fish.
Step 2: Analyzing the Options:
- (1) This option focuses on the lack of light, but the inefficiency is more about the adaptation process of cavefish.
- (2) This option is supported by the passage, as it explains how compensations like more tastebuds make up for the inefficiency.
- (3) This option is not directly mentioned as a cause of inefficiency in the passage.
- (4) This option aligns with the passage, explaining how the inefficiency is an unavoidable part of cavefish development.
Step 3: Conclusion:
Option (4) is the best explanation for why the inefficiency is unavoidable.
Top Questions on Reading Comprehension
- Shown below are letters ‘e’ taken from four popular logos, arranged in a sequence. Which of the options is the correct sequence?
- UCEED - 2026
- English Language Comprehension
- Reading Comprehension
- Shown below are four options, each showing consecutive frames representing the movement of a pendulum of an old-style wall clock for an animation movie. Which is the correct option?
- UCEED - 2026
- English Language Comprehension
- Reading Comprehension
- Acrucial moderating factor in how people experience comparisons is self-esteem. Individuals with high self-esteem are more likely to interpret upward comparison as informative rather than threatening. They are more resilient in the face of others’ success and more likely to believe they can reach their own goals. In contrast, people with low self-esteem are more prone to interpret comparison as judgment, reinforcing negative self-views and triggering feelings of inadequacy.
This dynamic creates a self-reinforcing loop. People with high self-esteem are less vulnerable to upward comparison, which intensifies those doubts. Those with a secure sense of self are more likely to use comparison as a learning tool. The same external stimulus—a colleague’s achievements, a friend’s popularity—can have radically different effects depending on internal stability.
Self-esteem also influences how people choose their comparison targets. Research has found that individuals often engage in “selective comparison,” seeking out those who confirm their existing beliefs about themselves. This can become a subtle form of self-sabotage. Someone who feels unworthy may subconsciously seek out targets that reinforce that sense, perpetuating a narrative of inferiority. One of the most promising antidotes to social comparison is temporal comparison—evaluating oneself not against others, but against one’s own past. This method has been shown to increase motivation and satisfaction, especially when individuals can see concrete progress. Temporal comparison activates the same reward circuits as social comparison but avoids the threat systems associated with social ranking. It also reinforces agency: individuals focus on what they can control and improve rather than what others control. In therapeutic and coaching settings, temporal comparison is used to help clients build self-efficacy and track growth over time.
Moreover, people who focus on self-improvement rather than social dominance are less likely to fall into cycles of envy or self-pity. They can still use others as inspiration, but they do so without attaching their self-worth to the outcome. This is not to say they never compare—but that they focus on learning, rather than judgment. The most skilful approach to comparison may lie in eliminating it, but in reframing it as feedback. When we interpret comparison as information rather than a verdict, we can ask, “What can I learn from this?” This shift turns comparison into a growth tool. Teachers mentor their students, not as rivals. Psychologists emphasize that the key variable here is mindset.
A fixed mindset sees comparison as a threat. If someone else is better, it means we are worse. A growth mindset sees comparison as a map. If someone else has reached a certain level, it means the path exists. This reframing is not just a cognitive trick. It changes the emotional tone of comparison, making it more likely to inspire than to wound. Reframing also requires emotional regulation—the ability to notice an initial pang of envy or shame without reacting impulsively. With practice, individuals can learn to pause, reflect, and reinterpret their emotional responses. Over time, this builds resilience and self-trust, allowing comparison to become a learning tool rather than a cage.- XAT - 2026
- Verbal and Logical Ability
- Reading Comprehension
When people who are talking don’t share the same culture, knowledge, values, and assumptions, mutual understanding can be especially difficult. Such understanding is possible through the negotiation of meaning. To negotiate meaning with someone, you have to become aware of and respect both the differences in your backgrounds and when these differences are important. You need enough diversity of cultural and personal experience to be aware that divergent world views exist and what they might be like. You also need the flexibility in world view, and a generous tolerance for mistakes, as well as a talent for finding the right metaphor to communicate the relevant parts of unshared experiences or to highlight the shared experiences while demphasizing the others. Metaphorical imagination is a crucial skill in creating rapport and in communicating the nature of unshared experience. This skill consists, in large measure, of the ability to bend your world view and adjust the way you categorize your experiences. Problems of mutual understanding are not exotic; they arise in all extended conversations where understanding is important.
When it really counts, meaning is almost never communicated according to the CONDUIT metaphor, that is, where one person transmits a fixed, clear proposition to another by means of expressions in a common language, where both parties have all the relevant common knowledge, assumptions, values, etc. When the chips are down, meaning is negotiated: you slowly figure out what you have in common, what it is safe to talk about, how you can communicate unshared experience or create a shared vision. With enough flexibility in bending your world view and with luck and charity, you may achieve some mutual understanding.
Communication theories based on the CONDUIT metaphor turn from the pathetic to the evil when they are applied indiscriminately on a large scale, say, in government surveillance or computerized files. There, what is most crucial for real understanding is almost never included, and it is assumed that the words in the file have meaning in themselves—disembodied, objective, understandable meaning. When a society lives by the CONDUITmetaphor on a large scale, misunderstanding, persecution, and much worse are the likely products.- XAT - 2026
- Verbal and Logical Ability
- Reading Comprehension
Later, I realized that reviewing the history of nuclear physics served another purpose as well: It gave the lie to the naive belief that the physicists could have come together when nuclear fission was discovered (in Nazi Germany!) and agreed to keep the discovery a secret, thereby sparing humanity such a burden. No. Given the development of nuclear physics up to 1938, development that physicists throughout the world pursued in all innocence of any intention of finding the engine of a new weapon of mass destruction—only one of them, the remarkable Hungarian physicist Leo Szilard, took that possibility seriously—the discovery of nuclear fission was inevitable. To stop it, you would have had to stop physics. If German scientists hadn’t made the discovery when they did, French, American, Russian, Italian, or Danish scientists would have done so, almost certainly within days or weeks. They were all working at the same cutting edge, trying to understand the strange results of a simple experiment bombarding uranium with neutrons. Here was no Faustian bargain, as movie directors and other naifs still find it intellectually challenging to imagine. Here was no evil machinery that the noble scientists might hide from the problems and the generals. To the contrary, there was a high insight into how the world works, an energetic reaction, older than the earth, that science had finally devised the instruments and arrangements to coart forth. “Make it seem inevitable,” Louis Pasteur used to advise his students when they prepared to write up their discoveries. But it was. To wish that it might have been ignored or suppressed is barbarous. “Knowledge,” Niels Bohr once noted, “is itself the basis for civilization.” You cannot have the one without the other; the one depends upon the other. Nor can you have only benevolent knowledge; the scientific method doesn’t filter for benevolence. Knowledge has consequences, not always intended, not always comfortable, but always welcome. The earth revolves around the sun, not the sun around the earth. “It is a profound and necessary truth,” Robert Oppenheimer would say, “that the deep things in science are not found because they are useful; they are found because it was possible to find them.”
...Bohr proposed once that the goal of science is not universal truth. Rather, he argued, the modest but relentless goal of science is “the gradual removal of prejudices.” The discovery that the earth revolves around the sun has gradually removed the prejudice that the earth is the center of the universe. The discovery of microbes is gradually removing the prejudice that disease is a punishment from God. The discovery of evolution is gradually removing the prejudice that Homo sapiens is a separate and special creation.- XAT - 2026
- Verbal and Logical Ability
- Reading Comprehension
Questions Asked in CAT exam
- The passage given below is followed by four summaries. Choose the option that best captures the essence of the passage.
In the dynamic realm of creativity, artists often find themselves at the crossroads between drawing inspiration from diverse cultures and inadvertently crossing into the territory of cultural appropriation. Inspiration is the lifeblood of creativity, driving artists to create works that resonate across borders. In a globalized era of the modern world, artists draw from a vast array of cultural influences. When approached respectfully, inspiration becomes a bridge, fostering understanding and appreciation of cultural diversity. However, the line between inspiration and cultural appropriation can be thin and easily blurred.
Cultural appropriation occurs when elements from a particular culture are borrowed without proper understanding, respect, or acknowledgment. This leads to the commodification of sacred symbols, the reinforcement of stereotypes, and the erasure of the cultural context from which these elements originated. It is essential to recognize that the impact of cultural appropriation extends beyond the realm of artistic expression, influencing societal perceptions and perpetuating power imbalances.- CAT - 2025
- Para Summary
- The number of distinct integers $n$ for which $\log_{\left(\frac14\right)}(n^2 - 7n + 11)>0$ is:
- CAT - 2025
- Linear Inequalities
- In the set of consecutive odd numbers $\{1, 3, 5, \ldots, 57\}$, there is a number $k$ such that the sum of all the elements less than $k$ is equal to the sum of all the elements greater than $k$. Then, $k$ equals?
- CAT - 2025
- Number Systems
- The number of distinct pairs of integers $(x, y)$ satisfying the inequalities $x>y \ge 3$ and $x + y<14$ is:
- CAT - 2025
- Number Systems
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is:
- CAT - 2025
- Linear Inequalities