Previous Year UPSC Questions

Explanation

Turkey is uniquely positioned between the Black Sea and the Mediterranean Sea. The Black Sea lies to the north of Turkey, while the Mediterranean Sea lies to the south. The coun-try also controls the Bosphorus Strait and the Dardanelles, which are critical waterways connecting the Black Sea to the Mediterranean via the Sea of Marmara. It is a transcontinental country, meaning it spans two continents: Europe and Asia.

Option (a), (c) and (d) are incorrect:

Turkey borders the Black Sea to the north but it does not border the Caspian Sea. The Caspian Sea is located further east, between countries like Russia, Kazakhstan, Iran, and Azerbaijan. The Gulf of Suez is located in Egypt, near the Red Sea. It is part of the Suez Canal that connects the Mediterranean Sea to the Red Sea. Turkey is not located near the Gulf of Suez. The Gulf of Aqaba and the Dead Sea are located in the Middle East, near countries like Israel, Jordan, and Saudi Arabia. Turkey does not share border with either of these bodies of water.

Explanation

Option (c) is correct: The correct sequence of cities in South-East Asia as one proceeds from south to north would be Jakarta>Singapore>Bangkok>Hanoi. Jakarta is the capital of Indonesia and is located on the island of Java approximately at 6.2°S (south of the equator). It is the southernmost city among the four listed. Singapore is a city-state located at the southern tip of the Malay Peninsula at approximately 1.3°N (just north of the equator). It is north of Jakarta. Bangkok is the capital of Thailand and is located in the central part of the country at approximately 13.8°N. It is north of Singapore and Jakarta. Hanoi is the capital of Vietnam and is located in the northern part of the country. At approximately 21.0°N. It is the northernmost city among the four listed.

Explanation

Indian rock-cut architecture includes Badami caves (6th century AD), Barabar caves for the Ajivikas (3rd century BC), and Ellora caves (5th-10th centuries AD), showcasing diverse religious traditions like Hinduism, Buddhism, and Jainism, with remarkable architectural complexity.

Statement 1 is incorrect: Badami caves were constructed by the Chalukya dynasty, in their capital Badami, which was earlier known as Vatapinagar. Barabar caves are the oldest surviving rock-cut caves in India.

Statement 2 is incorrect: The Barabar Caves were patronized by Emperor Ashoka and his successors. These are located in Jehanabad district, Bihar.

Statement 3 is correct: Ellora caves are a complex of Hindu (Caves 13-29), Buddhist (Caves 1-12) and Jain (Caves 30-34) monuments. These were built during the Rashtrakuta dynasty. It was designated as a World heritage site by UNESCO.

Explanation

Decomposers are organisms that primarily feed on dead organisms or the waste from living organisms. Some organisms perform a similar function as decomposers, and are some-times called detritivores. The difference lies in the way decomposers and detritivores break down organic material. Detritivores must digest organic material within their bodies in order to break it down and gain nutrients from it. Decomposers do not need to digest organic material internally in order to break it down. Fungi and Bacteria are examples of decomposers. Scavengers are the one among the first to arrive at a dead organism’s remains. It includes jack-als, wolves, raccoons, and opossums.

Explanation

Ecological succession is the process by which the structure of a biological community evolves over time. In grasslands, the dominance of grasses over trees is maintained due to specific environmental factors.

Option (c) is correct: Grasslands are found in regions with seasonal rainfall or semi-arid conditions where water availability is limited. Grasses are more drought-resistant than trees and can survive with less water. Grasslands are often subject to frequent fires which prevent the establishment of trees. Grasses can quickly regenerate after a fire while trees are more vulnerable and less likely to survive. Thus these factors together maintain the dominance of grasses and prevent the succession to a forest ecosystem.

Option (a), (b) and (d) are incorrect:

Insects and fungi play roles in ecosystems but they are not the primary factors preventing trees from replacing grasses in grasslands. Insects and fungi can affect plant health but they do not determine the overall structure of grassland ecosystems. Limited Sunlight and Paucity of Nutrients are not the primary limiting factor for tree growth. In fact grasses are highly efficient at utilizing available nutrients and sunlight which allows them to dominate these ecosystems.

Explanation

The Harappan Civilization, discovered in 1921 at Harappa (Pakistan), spanned Punjab, Sindh, Balochistan, Gujarat, Rajasthan, and western Uttar Pradesh, predating Chalcolithic cultures and showing greater development.

Statement 1 is incorrect: The Indus Valley Civilization differed from Mesopotamian and Egyptian civilizations, as it lacked grand palaces and temples ruled by powerful kings or priests. Instead, archaeological evidence suggests that their cities featured well-planned structures, public buildings, and granaries, emphasizing urban planning and administrative efficiency rather than monumental architecture.

Statement 2 is correct: Seals and figurines, such as the Priest-King and various fertility symbols, imply reverence for deities associated with fertility, nature, and possibly mother goddesses, indicating a worship system that involved both male and female divine figures.

Statement 3 is incorrect: No trace of Horses has been found in the Indus Valley. The use of chariots is associated with later cultures, such as the Vedic civilization, and is not a feature of the Indus Civilization.

Explanation

Productivity is the rate of biomass production. It is measured in mass per unit volume per unit time. The quantity of biomass or organic matter created by plants during photosynthesis per unit area during a certain time is referred to as primary production. Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is utilized by plants in respiration.

Option (c) is correct: The correct sequence of ecosystems in decreasing order of productivity is Mangroves > Grasslands > Lakes > Oceans Mangroves have the highest productivity due to abundant nutrients, tidal action, and high photosynthetic rates making them crucial breeding grounds for marine life (NPP: ~2000 gC/m²/year). Grasslands follow, as they receive ample sunlight but have moderate water availability, supporting rapid grass growth (NPP: ~600-1500 gC/m²/year). Lakes are less productive than grasslands because nutrient availability varies with depth and type (eutrophic lakes are more productive than oligotrophic ones) (NPP: ~300-1000 gC/m²/year). Oceans have the lowest productivity, as vast open waters are nutrient-poor, and deep layers receive minimal sunlight, though coastal areas and coral reefs are exceptions (NPP: ~50-200 gC/m²/year).

Explanation

Food Chain is the successive transfer of nutrients and energy from one creature to another. A food chain shows a straightforward relationship and only one component of the food or energy flow. E.g. Grasses Grasshopper Frog Snake Hawk/Eagle.

Statement 1 is correct: A food chain is a linear flow of energy and nutrients from one organism to another. Primary producers primary consumers secondary consumers tertiary consumers. Statements 2 and 3 are incorrect:

Food chains are not limited to a single species or population. They involve multiple species across different trophic levels (e.g., producers, primary consumers, secondary consumers). A food chain represents interactions between different species, not within a single population. A food chain does not illustrate the numbers of organisms eaten by others. It shows the sequence of energy transfer and feeding relationships. The number of organisms at each trophic level is better represented by a food web or ecological pyramid (e.g., pyramid of numbers, pyramid of biomass).

Explanation

An ecological niche refers to both the physical space an organism occupies and its functional role in an ecosystem, including its interactions with other organisms, resource utilization, and contribution to energy flow and nutrient cycling. The concept was introduced by Joseph Grinnell (1917) and further developed by G. Evelyn Hutchinson (1957).

Option (a), (c) and (d) are incorrect:

Ecotone is transition zone between two different ecosystems such as a mangrove forest between land and sea. It does not define the functional role of an organism. Habitat is the physical location where an organism lives (e.g., a pond for a frog) but does not describe its interactions and role in the ecosystem. Home range is the area in which animal regularly moves within for feeding and other activities, but it does not account for ecological interactions.

Explanation

Mycorrhizae is a symbiotic association between a fungus and a plant. The term ‘mycorrhiza’ refers to the role of the fungus in the plant’s rhizosphere, its root system. Mycorrhiza plays important roles in plant nutrition, soil biology and soil chemistry.

Statement 1 is correct: Trees host mycorrhizal fungus in their roots so they can absorb nutrients from the ground and resist the drought condition. These fungi exchange the carbon from the tree for vital nutrients including nitrogen, phosphate, and potassium from the soil.

Statement 2 is correct: Mycorrhizal plants can withstand unfavourable soil conditions, high pH levels, droughts, and poisonous heavy metals.

Statement 3 is correct: Mycorrhizae are symbiotic relationships between plant roots and specific soil fungi that are important for the ecosystem’s nutrient cycling and that help shield plants from environmental and cultural stress. Additionally, mycorrhizal fungi’s synthesis of oxalic acid contributes to disease suppression.