Previous Year UPSC Questions

Explanation

Carbon fertilisation is the artificial enrichment of the atmosphere of greenhouses with carbon dioxide, an essential nutrient for plants and vegetables. It also goes by the name of "Carbon Dioxide Fertilization." It can be used to grow nearly any form of vegetable (asparagus, celery, lettuce, tomatoes, aubergines, etc.), greenhouse fruit (strawberries), and ornamental plants, and is especially suited for cold climates.

Option (a) is correct: Carbon fertilisation results in an increase in the instantaneous rate of photosynthesis in C3 plants; and increases the transpiration efficiency of the leaf (C3 and C4 plants). During high concentration of carbon dioxide, plants maintain narrow openings of leaf surface which protects them from water loss. Faster plant growth enhances food production and allows for the sequestration of more carbon dioxide. Plants distribute a greater proportion of photosynthate to roots under high concentrations of atmospheric carbon dioxide. The reproductive biomass growth, as well as vegetative biomass growth, is usually increased by elevated carbon dioxide.

Explanation

Birds can act as carriers of plant pathogens. As they move through crops, pathogens may stick to their feathers, beaks, or feet, transferring them from infected plants to healthy ones. Dust particles often carry fungal spores or bacterial cells. When dust is blown by the wind, these pathogens can travel to new areas, causing infections in plants far from the original source. Rainwater, particularly during heavy downpours or storms, can facilitate the spread of pathogens. Raindrops pick up pathogens from infected plants or soil and splash them onto healthy plants, promoting disease transmission. Wind plays a significant role in transporting pathogens such as fungal spores, bacteria, or insect vectors contaminated with viruses. This mechanism allows pathogens to infect plants located far from the initial infection site.

Explanation

Statement 1 is incorrect: Soil water holding capacity is the amount of water that a given soil can hold for crop use. Soil texture and organic matter are the key components that determine soil water holding capacity. Organic matter influences the physical conditions of a soil in several ways.

Statement 2 is incorrect: Sulphur is one of three nutrients that are cycled between the soil, plant matter and the atmosphere. The sulphur cycle describes the movement of sulphur through the atmosphere, mineral and organic forms, and through living things.

Statement 3 is correct: Salinization is a major problem associated with irrigation, because deposits of salts build up in the soil and can reach levels that are harmful to crops.

Explanation

Conservation Agriculture (CA) is a farming system that promotes minimum soil disturbance (i.e. no tillage), maintenance of a permanent soil cover, and diversification of plant species. It enhances biodiversity and natural biological processes above and below the ground surface, which contribute to increased water and nutrient use efficiency and to improved and sustained crop production. According to FAO’s website there are three principles of Conservation of Agriculture:

1. Minimum mechanical soil disturbance: It refers to low disturbance no-tillage and direct seeding. The disturbed area must be less than 15 cm wide or less than 25% of the cropped area (whichever is lower).

2. Permanent soil organic cover: Three categories are distinguished: 30-60%, >60-90% and >90% ground cover, measured immediately after the direct seeding operation. An area with less than 30% cover is not considered as CA.

3. Species diversification: Rotation/association should involve at least 3 different crop species. The rotation of crops is not only necessary to offer a diverse "diet" to the soil micro organisms, but as they root at different soil depths, they are capable of exploring different soil layers for nutrients.

Explanation

Sthanakvasi is a branch of Svetambara Jainism that was started in 1653 AD by a merchant named Lavaji. It holds that the path to soul purification and achieving Nirvana/Moksha does not include idol worship.

Option (b) is correct:

The Sthanakvasi sect is a reformist sect within Jainism. It emerged in the 15th century CE as a reaction against the perceived ritualism and temple-centric practices of the Murtipujaka (idol-worshipping) Jains.mThe Sthanakvasis emphasize asceticism, non-violence (ahimsa), and meditation. They reject the worship of idols and instead focus on spiritual practices and the study of Jain scriptures.mThe sect derives its name from the term "Sthanak", meaning a place of worship, which is typically a simple hall rather than an ornate temple.

Explanation

A Bodhisattva in Buddhism is an enlightened being who, out of compassion, chooses to remain in the cycle of birth and death (samsara) to help all sentient beings attain liberation. The Bodhisattva path emphasizes the cultivation of perfections (paramitas) like generosity, wisdom, and patience to achieve Buddhahood. According to Buddhist tradition, Maitreya is a Bodhisattva who will appear on earth in future, attain enlightenment and teach pure dharma. He will be the future Buddha. Avalokiteshvara (The Lord Who Looks Down), also called Padmapani (The Lotus-Bearer) and Lokesvara in Sanskrit (The Lord of the World) is believed to hear the cries of suffering beings and assist in their liberation, offering help and comfort. The Bodhisattva is often depicted with multiple arms, symbolizing the ability to reach out and help countless beings simultaneously.

Explanation

Statement 1 is correct: Coral reefs predominantly thrive in warm, shallow waters, typically between the Tropics of Cancer and Capricorn (30°N to 30°S latitude). These tropical regions provide the ideal conditions--such as appropriate temperature, light, and salinity--for coral growth. The warm water temperatures are essential for the symbiotic relationship between coral polyps and the algae (zooxanthellae) that live within their tissues.

Statement 2 is correct: The Great Barrier Reef in Australia, along with coral reef systems in Indonesia and the Philippines (part of the Coral Triangle), collectively account for more than one-third of the world’s coral reefs. These regions are globally renowned for their extensive and diverse coral systems.

Statement 3 is correct: Coral reefs are among the most bio-diverse ecosystems on Earth, hosting over 25,000 described species from 32 of the 33 known animal phyla, which is more than the number of animal phyla found in tropical rainforests.

Explanation

GPS technology uses a network of satellites to pinpoint a user’s location on Earth. By receiving signals from multiple satellites, GPS devices can calculate precise latitude, longitude, and altitude coordinates. This technology has revolutionized navigation, transportation, and many other fields. Options 1 is correct: Smartphones use GPS to determine the user’s precise location which enables location-based services such as navigation, ride-sharing apps, geotagging, and emergency location tracking. Option 2 is correct: Financial institutions use GPS-derived time stamps to record the exact time of transactions, aiding in audit trails and fraud detection. GPS ensures that banking systems across different locations operate in sync, which is crucial for real-time processing and settlements. Options 3 is correct: GPS provides precise time references that are vital for synchronizing the operations of power grids, helping in load balancing and efficient energy distribution.

Explanation

Option (b) is correct: The scenario described is a classic example of the Internet of Things (IoT). IoT refers to a network of interconnected devices that communicate and exchange data with each other to automate tasks and improve efficiency. The smartphone, geyser, smart mirror, refrigerator, and car are all IoT devices.

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

Border Gateway Protocol is used to manage how data packets are routed across the internet between different autonomous systems (networks). It is primarily used by internet service providers (ISPs) and large organizations to ensure efficient data routing. Internet Protocol (IP) is a fundamental communication protocol used for transmitting data over the internet. It provides the addressing system (IP addresses) that allows devices to communicate. Virtual Private Network is a technology that creates a secure, encrypted connection over the internet to protect user privacy and data. It is commonly used to access restricted networks or hide online activity.

Explanation

Sand mining is the extraction of sand, mainly through an open pit (or sandpit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds.

Statement 1 is incorrect: Sand mining typically does not directly affect the salinity of the river. Salinity is more influenced by factors like the influx of seawater in coastal areas, evaporation rates, and the presence of saline minerals in the riverbed.

Statement 2 is correct: The amount of suspended particles in the water at the excavation site and downstream increases due to increased riverbed and bank erosion. This process stirs up the sediments and increases the chance of contamination of groundwater.

Statement 3 is correct: Heavy sand mining causes removal of sand and gravels from the riverbed. Due to this the groundwater table drops leaving the drinking water wells on the embankments of these rivers dry. Alteration of rivers, damage to river biodiversity, altered sediment budget lead to poor water quality, worsen water scarcity threat to coastal communities, damage to public and private property.