Day-701 | Daily MCQs | UPSC Prelims | SCIENCE AND TECHNOLOGY

Answer: A
Explanation
Statement 1 is correct: PCR is a technique used to amplify specific regions of DNA, making it possible to generate millions of copies of a particular DNA sequence.
Statement 2 is incorrect: PCR requires a DNA polymerase enzyme that can withstand high temperatures because the technique involves cycles of heating and cooling to denature DNA, anneal primers, and extend DNA strands.
Statement 3 is incorrect: PCR can be performed using DNA samples from various sources, not just human cells. It is widely used in molecular biology and biotechnology to amplify DNA from diverse organisms, including bacteria, plants, animals, and viruses.

Answer: B
Explanation
Statement 1 is incorrect: Leukemia primarily affects white blood cells (or leukocytes), not thrombocytes or red blood cells. It is a cancer of the blood and bone marrow characterized by the rapid production of abnormal white blood cells.
Statement 2 is correct: Leukemia is a type of cancer originating from bone marrow stem cells. In leukemia, these stem cells undergo malignant transformation, leading to the uncontrolled production of abnormal white blood cells.
Statement 3 is correct: Exposure to certain environmental toxins or radiation may increase the risk of developing leukemia. Leukemia can also result from genetic factors, such as chromosomal abnormalities, and other unknown causes.

Answer: D
Explanation
The glycemic index is a measure used to determine how much a food can affect the blood sugar levels.
Foods are classified as low, medium, or high glycemic foods and ranked on a scale of 0–100.
● Low: 55 or less
● Medium: 56–69
● High: 70 or above
Foods high in refined carbs and sugar are digested more quickly and often have a high GI, while foods high in protein, fat, or fiber typically have a low GI. Foods that contain no carbs are not assigned a GI and include meat, fish, poultry, nuts, seeds, herbs, spices, and oils. Thus, GI is a tool to promote better blood sugar management among people prone to type 2 diabetes.
The glycemic index of lactose is 46 to 65. For comparison, the glycemic index of glucose is 100 to 138, of sucrose is 68 to 92, of maltose is 105, and of fructose is 19 to 27. Lactose has relatively low cariogenicity among sugars.
Thus, mother’s milk contains lactose which has a lower glycemic index than baby food which are produced by FMCG companies which are largely maltose.
In April 2024, there were allegations of Nestle selling baby food products with higher sugar content in India.

Answer: D
Explanation
Statement 1 is incorrect: Subsonic cruise missiles use jet propulsion technology rather than ramjet engines. Jet engines have rotating parts to generate thrust unlike ramjets which use high velocity of incoming air to generate thrust.
Jet engines, which are also called gas turbines, work by sucking air into the front of the engine using a fan. From there, the engine compresses the air, mixes fuel with it, ignites the fuel/air mixture, and shoots it out the back of the engine, creating thrust.
However, a ramjet is a variant of an air breathing engine that does not include a rotary compressor; rather, it uses the engine’s forward motion to compress the incoming air.
Moreover, supersonic cruise missiles which operate at speeds about Mach 3 (1 Mach is the speed of sound in air). They use scramjet technology to generate thrust.
Thus, the first part of statement 1 is incorrect whereas the 2nd part of the statement is correct. So, the statement is considered to be incorrect.
Statement 2 is correct: For effective generation of thrust to propel missiles forward, there is a need to operate air breathing propulsion systems like ramjets and scramjets at speeds greater than Mach 1. So, ramjets and scramjets cannot function at zero or low airspeed.

Answer: C
Explanation
Statement 1 is correct: Weak AI, also called narrow AI, is capable of performing a specific task that it’s designed to do, such as recommending movies, giving us directions, or even helping us pick the perfect playlist. Strong AI, on the other hand, is capable of learning, thinking and adapting like humans do. That said, strong AI systems don’t actually exist yet.
Statement 2 is correct: Generative AI is a subfield of AI that focuses on creating systems capable of generating new and original content, such as images, text, music, or even video whereas Artificial General Intelligence a form of artificial intelligence that is as capable as human intelligence in a wide variety of cognitive tasks. This means that general AI would be able to learn and reason in multiple domains, adapt to new situations, understand context and perform a wide range of tasks with a high degree of autonomy. Thus, Generative AI is still an advanced version of narrow AI which can leverage machine intelligence to create content but still it has lower intelligence in terms of autonomy to perform tasks which can be associated with AGI.
Statement 3 is correct: Artificial superintelligence is an AI system that is self-aware and intelligent enough to surpass the cognitive abilities of humans. This is still a theoretical concept as these machines will be possessing consciousness which would be far superior to those possessed by normal human beings.