CAT 2021 Slot 3 — VARC Question 1
Direction for Reading Comprehension: The passages given here are followed by some questions that have four answer choices; read the passage carefully and pick the option whose answer best aligns with the passage.
Back in the early 2000s, an awesome thing happened in the New X-Men comics. Our mutant heroes had been battling giant robots called Sentinels for years, but suddenly these mechanical overlords spawned a new threat: Nano-Sentinels! Not content to rule Earth with their metal fists, these tiny robots invaded our bodies at the microscopic level. Infected humans were slowly converted into machines, cell by cell.
Now, a new wave of extremely odd robots is making at least part of the Nano-Sentinels story come true. Using exotic fabrication materials like squishy hydrogels and elastic polymers, researchers are making autonomous devices that are often tiny and that could turn out to be more powerful than an army of Terminators. Some are 1-centimetre blobs that can skate overwater. Others are flat sheets that can roll themselves into tubes, or matchstick-sized plastic coils that act as powerful muscles. No, they won't be invading our bodies and turning us into Sentinels - which I personally find a little disappointing - but some of them could one day swim through our bloodstream to heal us. They could also clean up pollutants in water or fold themselves into different kinds of vehicles for us to drive. . . .
Unlike a traditional robot, which is made of mechanical parts, these new kinds of robots are made from molecular parts. The principle is the same: both are devices that can move around and do things independently. But a robot made from smart materials might be nothing more than a pink drop of hydrogel. Instead of gears and wires, it's assembled from two kinds of molecules - some that love water and some that avoid it - which interact to allow the bot to skate on top of a pond.
Sometimes these materials are used to enhance more conventional robots. One team of researchers, for example, has developed a different kind of hydrogel that becomes sticky when exposed to a low-voltage zap of electricity and then stops being sticky when the electricity is switched off. This putty-like gel can be pasted right onto the feet or wheels of a robot. When the robot wants to climb a sheer wall or scoot across the ceiling, it can activate its sticky feet with a few volts. Once it is back on a flat surface again, the robot turns off the adhesive like a light switch.
Robots that are wholly or partly made of gloop aren't the future that I was promised in science fiction. But it's definitely the future I want. I'm especially keen on the nanometre-scale "soft robots" that could one day swim through our bodies. Metin Sitti, a director at the Max Planck Institute for Intelligent Systems in Germany, worked with colleagues to prototype these tiny, synthetic beasts using various stretchy materials, such as simple rubber, and seeding them with magnetic microparticles. They are assembled into a finished shape by applying magnetic fields. The results look like flowers or geometric shapes made from Tinkertoy ball and stick modelling kits. They're guided through tubes of fluid using magnets, and can even stop and cling to the sides of a tube.
Which one of the following scenarios, if false, could be seen as supporting the passage?
Answer & solution
- A
Some hydrogels turn sticky when an electric current is passed through them; this potentially has very useful applications.
- B
Robots made from smart materials are likely to become part of our everyday lives in the future.
Nano-Sentinel-like robots are likely to be used to inject people to convert them into robots, cell by cell.
- D
There are two kinds of molecules used to make some nano-robots: one that reacts positively to water and the other negatively.
Easy
This is an inverted question: it asks which scenario, if false, would support the passage. That means the right answer is the statement which, if it were true, would clash with the passage. So scan for the option that contradicts what the author actually says; the three options that merely restate the passage are the wrong ones here.
Supports the passage (so not the answer). Paragraph 4 describes exactly this: a hydrogel that "becomes sticky when exposed to a low-voltage zap of electricity" and is useful for letting robots climb walls and ceilings. As a true statement it aligns with the passage, so its being false would not support it.
Supports the passage (so not the answer). The closing paragraphs ("it's definitely the future I want") and the examples of healing, cleaning water and forming vehicles point to these robots entering everyday life. A true statement, consistent with the text.
Contradicts the passage — this is the answer. Paragraph 2 explicitly denies the cell-by-cell conversion idea: "No, they won't be invading our bodies and turning us into Sentinels." So this statement, if true, opposes the passage; therefore it is the one that, if false, would support the passage.
Supports the passage (so not the answer). Paragraph 3 says these bots are assembled from "two kinds of molecules - some that love water and some that avoid it." A faithful restatement.
Option C is correct. It is the only statement that conflicts with the passage (which expressly rules out bodily conversion), so its falsity would support the passage.