UPSC Previous Years (Prelims & Mains) Questions

Correct Answer : Option (C) - Only three

Note : HFCs are entirely man-made. They are primarily produced for use in refrigeration, air-conditioning, insulating foams and aerosol propellants, with minor uses as solvents and for fire protection.

Hence, option (c) is correct.

Source : ccacoalition

Correct Answer :   Orangutan

Note : Researchers have spotted orangutans using sticks to extract seeds from fruit and scrape insects using a stick from a hole in a tree in the wild. Hence, option (b) is correct.

Source : Inverse

Correct Answer : Option (C) - All three

Note : Hyperthermophilic (‘superheat-loving’) bacteria and archaea are found within high-temperature environments. Hence, statement 1 is correct.

Microorganisms live in every part of the biosphere, and some of them are even capable of growing at low temperatures, including those below the freezing point. These microorganisms live in the sea or in high mountains. Hence, statement 2 is correct.

Acidophiles are microorganisms that show optimal growth in highly acidic environments. They are of two types. The extreme acidophiles dwell in environments with a pH value <3, and moderate acidophiles grow optimally in conditions having pH values ranging between 3 and 5. Hence, statement 3 is correct.

Correct Answer : Option (B) - Only two

Note : The Indian Squirrel nests at the top of the trees. Hence, statement 1 is NOT correct.

Indian squirrels are known to cache their food, especially nuts and seeds, for later consumption. They might bury them under leaves or hide them in small crevices in trees. This behavior helps them survive during lean times when food sources are scarce. Hence, statement 2 is correct.

Indian squirrels are omnivores. They feed mainly on nuts and fruits but will also eat seeds, insects, small mammals and reptiles, eggs, and even sometimes chicks of birds. Hence, statement 3 is correct.

Source : a-z-animals

Correct Answer : Option (D) - All Four

Note : * Mushrooms act as antibacterial, immune system enhancer and cholesterol lowering agents; additionally, they are important sources of bioactive compounds. As a result of these properties, some mushroom extracts are used to promote human health and are found as dietary supplements. Hence, statement 1 is correct.

* Magic mushrooms (psychoactive fungi) that grow in the United States, Mexico, South America, and many other parts of the world, contain psilocybin and psilocin, which are hallucinogens and are Class I controlled substances. Hence, statement 2 is correct.

* Fungi are living things, just like insects are, capable of evolving and adapting. Many synthetic pesticides have lost efficacy over the years because the target insects have just evolved and built-up tolerance to them. But like any other relationship between parasite and host, predator and prey, the fungus-based biopesticides have the ability to evolve right along with any adaptation the insects might come up with to hinder them. They are also nontoxic to humans and other wildlife. Hence, statement 3 is correct.

* A mushroom documentation project in the forests of Northeast India has revealed not only 600 varieties of fungi, but also led to a new discovery: a bioluminescent — or light emitting — variety of mushroom. Hence, statement 4 is correct.

Source : PMC

Correct Answer :   Honeybees

Note : * Honeybees perform waggle dance to communicate the location of food sources or new nest sites to their colony mates. Hence, option (c) is correct.

* The dance consists of a straight run followed by a loop to one side and then another straight run followed by a loop to the other side, forming a figure-eight pattern. The angle of the straight run relative to gravity indicates the direction of the food source relative to the sun, and the duration of the straight run indicates the distance of the food source from the hive.

* Young bees that were isolated from older foragers could perform waggle dance spontaneously, but they made more errors in encoding distance information than bees that had older role models.

Source : Science News

Correct Answer : Option (A) - Only one

Note : * The lion-tailed macaque is not a nocturnal animal. It is an arboreal and diurnal creature, they sleep at night in trees (typically, high in the canopy of rainforest). These macaques are territorial and very communicative animals. Hence, 1 is not correct.

* Malabar civet is primarily nocturnal. It is a small, carnivorous mammal that is native to the Western Ghats region of India.

* Sambar Deer is crepuscular and nocturnal but it is most active at dawn and dusk. Hence, 3 is not correct.

Hence, option (A) is correct.

Source : Animalia

Correct Answer :   The International Union for Conservation of Nature

Note : The Invasive Species Specialist Group (ISSG) is a global network of scientific and policy experts on invasive species, organized under the auspices of the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN). Hence, option (a) is correct.

It was established in 1994.

The ISSG manages the Global Invasive Species Database (GISD), which provides information on invasive alien species worldwide. The ISSG also maintains other online resources such as the Aliens-L listserv, the Invasive Species Compendium, the Global Register of Introduced and Invasive Species, and the Environmental Impact Classification for Alien Taxa.

Source : Iucn.org

Correct Answer : Option (C) - Statement-1 is correct Statement-II is incorrect

Note : * Marsupials are any members of the mammalian infraclass Marsupialia, characterised by premature birth and continued development of the newborn while attached to the nipples on the mother’s lower belly.

* They are known as pouched mammals, because the adult females have a marsupium, or pouch.

* Marsupials are not naturally found in India. There are over 330 species of marsupials. Around two-thirds of them live in Australia. The other third live mostly in South America, where some interesting ones include the flipper-wearing yapok, bare-tailed woolly opossum. Hence, statement-I is correct.

* However, marsupials can thrive in various habitats, not only in montane grasslands with no predators. They can live in any part of the forest habitat.


Therefore, option (c) is correct.

Source : Britannica

Correct Answer : Option (C) - Statement-I is correct but Statement-II is incorrect

Note : In India, power is generated from conventional (Thermal, Nuclear & Hydro) and renewable sources (Wind, Solar, Biomass etc).

However, Major production of Electricity is achieved through coal, a thermal power plant which is around 75% of the total power generation. Hence, statement-I is correct.

However, uranium enriched to the extent of at least 60% is not required for the production of electricity. Uranium enrichment is the process of increasing the concentration of uranium-235, which is the fissile isotope of uranium that can sustain a nuclear chain reaction.

For civilian nuclear power plants, uranium is typically enriched to about 3-5% of uranium-235, which is sufficient for light water reactors that are commonly used for electricity generation. Hence, statement-II is not correct.

Hence, option (c) is correct.

Source