Previous Year UPSC Questions

Explanation

Statement 1 is correct: Tapeworms, belonging to the class Cestoda are fascinating parasites with a unique reproductive strategy. Each segment of their body, called a proglottid, contains both male and female reproductive organs, making them hermaphroditic. This adaptation allows tapeworms to self-fertilize or cross-fertilize, ensuring reproductive success even in limited host environments. Their reproductive efficiency is one reason they thrive as internal parasites.

Statement 2 is correct: Roundworms, or nematodes (phylum Nematoda), exhibit sexual dimorphism, meaning individuals are either male or female. Males are typically smaller and possess specialized structures like spicules for mating. This separation of sexes enhances genetic diversity, a critical factor for survival in diverse environments. Nematodes are one of the most abundant and diverse groups of animals on Earth, found in almost every ecosystem.

Statement 3 is correct: Filariasis is caused by parasitic nematodes like Wuchereria bancrofti and Brugia malayi, which are transmitted to humans via mosquito vectors. These tiny worms reside in the lymphatic system, causing lymphatic filariasis (commonly called elephantiasis). This disease exemplifies the intricate relationship between hosts, parasites, and vectors. Nematodes like these highlight the importance of vector control in managing parasitic diseases.

Statement 4 is incorrect: The Guinea worm (Dracunculus medinensis) is not an annelid (segmented worm) but a nematode. This parasitic roundworm causes dracunculiasis, a disease associated with painful blister formation as the adult worm emerges from the skin. Nematodes are unsegmented and possess a simple body structure adapted for parasitism. This parasite’s lifecycle is intricately linked to water sources, making safe drinking water a key preventive measure.

Explanation

A is correctly matched with 4: The Fohn is a warm, dry, downslope wind that occurs in the Alps. It’s a katabatic wind, meaning it’s created by air descending from a higher elevation. As air is forced up the windward side of a mountain range, it cools and condenses, losing its moisture as precipitation. The now dry air continues over the mountain crest and descends on the leeward side. As it descends, it compresses and warms, often significantly. This results in a sudden rise in temperature and a decrease in humidity on the leeward side, creating the characteristic Fohn wind. These winds can have a significant impact on local weather, causing rapid snowmelt, increasing the risk of avalanches, and even influencing vegetation patterns. B is correctly matched with 2: The Sarmun is a hot, dry, and dusty wind that blows in the Kurdistan region, particularly in northern Iraq and parts of Iran. It’s a type of desert wind, of-ten associated with low-pressure systems. These winds can carry large amounts of dust and sand, reducing visibility and causing discomfort. They are most common during the summer months and can lead to significant temperature increases and dry conditions, impacting agriculture and water resources. The Sarmun is similar to other regional desert winds like the Khamsin in Egypt or the Sirocco in the Mediterranean, although its specific characteristics and regional impact are unique to the Kurdistan area. C is correctly matched with 3: The Santa Ana winds are strong, dry, and warm winds that blow in Southern California. They originate from high-pressure systems over the Great Basin region and flow southwestward towards the coast. As the air descends from the higher elevations of the mountains surrounding Southern California, it compresses and warms, becoming very dry. These winds are channeled through canyons and mountain passes, increasing their speed and intensity. Santa Ana winds are known for their ability to rapidly increase fire danger, as they create extremely dry conditions and can quickly spread wildfires. They are most common in the fall and winter months and can also cause power outages and damage to property. D is correctly matched with 1: The Zonda is a dry and dusty wind that affects the western slopes of the Andes Mountains in Argentina. Similar to the Fohn, it’s a katabatic wind. Moist air is forced up the eastern slopes of the Andes, where it cools and releases its moisture. The dry air then descends on the western side, warming as it compresses. The Zonda is characterized by its hot and dry nature, often carrying dust and sand from the high-altitude deserts. It can cause significant temperature fluctuations and reduce visibility. These winds are most prevalent during the winter months and can have a significant impact on agriculture and local weather patterns in the affected regions of Argentina.

Explanation

Alexei Shirov is a Latvian-born Spanish chess grandmaster. He has represented Spain in international competitions since 1996.

Explanation

Anjali Vedpathak (Rifle Shooting): A top Indian rifle shooter, was ranked world No. 1 in the 10m air rifle event, with multiple international medals. Mouma Das (Table Tennis): A prominent Indian table tennis player, representing India in the Commonwealth Games and Olympics. Neelam Singh (Athletics): An Indian discus thrower, who competed in international events like the Asian and Commonwealth Games. Tumpa Debnath (Gymnastics): An Indian gymnast known for her performances in national and international gymnastics competitions.

Explanation

Statement (a) is correct: Goa attained full statehood on May 30, 1987 to become the 25th state of India. Statement (b) is correct: Diu is indeed an island located in the Gulf of Khambhat (Cambay), off the coast of Gujarat. It was part of Portuguese India until 1961. Statement (c) is correct: The 56th Amendment of the Constitution of 1987 led to Goa becoming a full-fledged state, while Daman and Diu continued as a Union Territory. Statement (d) is incorrect: Dadra and Nagar Haveli were not under French colonial rule. They were under Portuguese rule until 1954 when local freedom fighters and activists liberated the region and integrated into India in 1961.

Explanation

Keystone species play a crucial role in maintaining eco-system structure and function, having a disproportionate impact relative to their abundance. Like the keystone in an arch, they support the stability of the entire system. These species influence population sizes, modify the environment, and affect species diversity and community composition. Removing a keystone species can disrupt the ecosystem, leading to biodiversity loss and instability. Some of the Keystone Species are: Sea Otters(kelp forest ecosystem). Wolves and other top predators(Grassland ecosystem), Elephants(Savannah), Beavers and Starfish. Options (b), (c) and (d) are incorrect:

Allopatric species are species that evolve separately due to geographic isolation, Eg. African and Indian elephants. Sympatric species are species that evolve separately within the same geographic area. Threatened species are species at risk of becoming endangered in the near future due to factors like habitat loss, climate change, and human activities.

Explanation

Economic liberalization in India began with substantial changes in the industrial licensing policy under the New Economic Policy of 1991. The reforms aimed to reduce state control by delicensing industries, promoting competition, and encouraging private sector participation. This marked a departure from the License-Permit Raj of earlier decades.

Explanation

The expansion of British India was a significant aspect of British’s colonial policy, with the British seeking to expand the territory of British India through annexations, wars, and treaties.

Option (b) is correct:

The last major extension of British Indian territory occurred during Lord Dalhousie’s tenure as Governor-General (1848-1856). Dalhousie is particularly noted for his aggressive policy of annexation and territorial expansions. For example, under Doctrine of Lapse(Jhansi, Satara, Nagpur, etc) and on the basis of Misgovernance (Awadh) were annexed.

Explanation

DNA fingerprinting is biotechnique based on analysis of specific regions of DNA that are unique to each individual. This makes it a powerful forensic tool. Assertion (A) is true: DNA fingerprinting, also known as DNA profiling, has become a powerful tool in forensic science for identifying individuals. It is widely used to establish paternity and to identify suspects in criminal cases, including rape and assault. The unique genetic makeup of each individual allows forensic experts to match DNA samples from crime scenes with those of suspects or to determine biological relationships. Reason (R) is true: Trace evidence such as hair, saliva, and dried semen can provide sufficient DNA for analysis. Even small biological samples left at crime scenes can be collected and processed to extract DNA, which can then be compared to known samples to identify individuals. Both Assertion (A) and Reason (R) are true, and Reason (R) correctly explains why DNA fingerprinting is effective in establishing paternity and identifying criminals in rape and assault cases. The ability to analyze DNA from minimal trace evidence underpins the power of DNA fingerprinting in forensic investigations.

Explanation

Insect-resistant cotton, commonly known as Bt cotton, has been genetically engineered by inserting a gene from the bacterium Bacillus thuringiensis (Bt). This bacterium naturally produces a protein toxic to specific insect pests, such as bollworms, but is safe for humans and non-target organisms. The Bt gene produces a protein that disrupts the digestive system of the pests upon ingestion, ultimately killing them. Bt cotton has significantly reduced the dependence on chemical insecticides and has become a widely adopted technology for pest management in cotton farming.