Previous Year UPSC Questions

Explanation

Statement 1 is correct: Ocean acidification reduces the ability of calcareous phytoplankton (such as coccolithophores) to form their calcium carbonate shells. As the ocean becomes more acidic, the process of calcification is impaired, adversely affecting their growth and survival.

Statement 2 is correct: Coral reefs rely on the ability of coral polyps to produce calcium carbonate skeletons. As ocean acidity increases, it becomes more difficult for corals to build and maintain their skeletons, making them more vulnerable. This not only threatens corals themselves but also the ecosystems that depend on them.

Statement 3 is correct: The larvae of some marine organisms, particularly those with phytoplanktonic larvae, rely on calcium carbonate for protection and growth. As the ocean becomes more acidic, these organisms may face difficulties in developing their shells, which could disrupt marine food webs.

Statement 4 is incorrect: While phytoplankton contribute to the release of dimethyl sulfide (DMS), which is linked to cloud formation, ocean acidification does not have a direct and large-scale impact on cloud formation. The reduction in phytoplankton due to ocean acidification may lead to lower DMS emissions, but this effect is relatively minor and unlikely to significantly affect cloud seeding and formation.

Explanation

Statement 1 is correct: China has historically been the dominant global producer of rare earth elements, accounting for a significant share of the world’s supply. Concerns about supply disruptions have arisen due to China’s implementation of export restrictions, quotas, and other regulatory measures. These actions have included limiting export volumes, imposing ex-port tariffs, and consolidating its rare earth mining industry. These policies, while potentially aimed at domestic industrial development and resource conservation, have had significant impacts on global markets, creating price volatility and raising concerns about access to these crucial materials for other countries.

Statement 2 is incorrect: China, Australia, Canada, and Chile dominate the rare earth element market, but reserves are also found in Asia, Africa, Europe, and South America. Other countries like the USA, India, Russia, Brazil, Vietnam, and Myanmar also have significant rare earth deposits. While China remains the largest producer, global exploration and development efforts are underway to diversify supply due to challenges in mining operations elsewhere.

Statement 3 is correct: Rare earth metals are crucial for electronics, used in magnets, batteries, displays, and more. As global demand for electronic products and renewable energy grows, the need for these elements has risen, heightening concerns about supply security and their strategic economic importance.

Explanation

Article 51A of part IV-A of the Indian Constitution deals with the Fundamental Duties. These duties are the moral and civic obligations that all citizens of a nation have. In 1976, the Fundamental Duties were first recommended by the Swaran Singh Committee by 42nd Constitutional Amendment Act, 1976. One more Fundamental Duty was added by 86th Constitutional Amendment Act, 2002. List of Fundamental Duties are - To abide by the Constitution and respect National Flag and National Anthem (Not national song) To follow the noble ideals that inspired the struggle for freedom. To protect the sovereignty, unity and integrity of India. To render national service when called upon to do so. To promote the common spirit of brotherhood amongst all Indians and to renounce practices derogatory to the dignity of women. To preserve the rich heritage of the country’s culture. To protect the national environment including forests, lakes, wildlife, etc. To develop scientific temper, humanism and spirit of reform and inquiry. To safeguard public property and to abjure violence. To strive towards excellence in all spheres of individuals. To provide opportunity for education to his child between the age 6 and 14 years Thus, Protecting the weaker sections from social injustice is more relevant to Directive Principle of State Policy (DPSP), not Fundamental Duties.

Explanation

Chlorofluorocarbons, Hydrochlorofluorocarbons, Carbon tetrachloride, Methyl chloroform, Methyl chloroform, Ha-lons, Methyl bromide, etc. are Ozone Depleting Substances. Chlorofluorocarbons (CFCs) also referred to as ozone depleting materials, are used to make plastic foams, cleaning electronic components, and pressurising aerosol cAns: They are non-toxic, nonflammable chemicals containing atoms of carbon, chlorine and fluorine. Statements 1, 3 and 4 are correct: Chlorofluorocarbons, known as ozone-depleting substances, are used in the production of plastic foams, in cleaning electronic components, and as pressurising agents in aerosol.

Statement 2 is incorrect: Chlorofluorocarbons are not used in the production of tubeless tyres. Tubeless tyre is basically a clincher tyre inflated onto a rim with no inner tube. Instead of an inner tube holding the air pressure, an airtight chamber is created with a tubeless-specific tyre, developed with a special (commonly carbon) bead, and a compatible rim.

Explanation

Greenhouse Effect is a naturally occurring phenomenon that warms and covers the lower atmosphere of the planet, keeping it at a temperature where life may survive. The earth’s cooling and warming are balanced by them. Without this, the current 15 degrees Celsius average temperature of the earth’s surface would be -19 degrees Celsius. Human-induced greenhouse gas emissions upset the natural balance & lead to increased warmth.

Option (d) is correct: Carbon dioxide absorbs the infrared (IR) radiation emitted by the Earth’s surface. When sunlight reaches the Earth it warms the surface, which then re-emits this energy as infrared radiation. CO₂ molecules absorb this IR radiation, trapping heat in the atmosphere and causing the temperature to rise.The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere because it absorbs the infrared part of the solar radiation. It absorbs energy with a wavelength of 15 m (micrometres).

Explanation

In 1937, after the Government of India Act, 1935, which allowed for provincial autonomy, the Indian National Congress (INC) formed ministries in eight out of eleven provinces in India. Lord Linlithgow, the Viceroy of India, declared India’s involvement in World War II on behalf of the British government. As a result of this unilateral declaration Congress ministries resigned as a protest against the British government’s failure to consult Indian leaders regarding India’s participation in the war.

Explanation

The Big Bang theory states that at some point of time the entire space was contained in a single point of very high density and temperature, from where the Universe has been witnessing expansion in all directions ever since. According to Hubble’s law, the expansion of the universe is such that the velocity at which the galaxy is moving away from the observer is increasing with time.

Statement 1 is correct: Cosmic Microwave Background (CMB) is thought to be leftover radiation from the Big Bang, i.e., the time when the universe began. According to the theory, when the universe was born it underwent rapid inflation and expansion. (The universe is still expanding today, and the expansion rate appears different depending on observation). The CMB represents the heat left over from the Big Bang.

Statement 2 is correct: American astronomer Edwin Hubble was the first to describe the redshift phenomenon (galactic redshift) and tie it to an expanding universe (galaxies are drifting apart). Redshift and Blueshift describe how light changes with movement of objects in space closer or farther from us. While moving away, the light is shifted to the red end of the spectrum, as its wavelength gets longer. While moving closer, the light moves to the blue end of the spectrum, as its wavelength gets shorter. Galactic Redshift is related to the expanding Universe concept.

Statement 3 is incorrect: Movement of asteroids in space is due to gravity and it is not linked with the concept of expansion of the universe.

Statement 4 is incorrect: The occurrence of supernova explosions (powerful stellar explosions in which a single star becomes as bright as 109 stars like the sun) helps in studying the distribution of elements throughout the universe. These elements travel on to form new stars, planets and everything else in the universe. But this is not considered as evidence for the continued expansion of the universe.

Explanation

India follows a Parliamentary type of Government in which the President is the constitutional head of the state. He is the Executive head of India and all the executive powers of the Union shall be vested in him. The President lays Reports and Statements before the parliament of the following bodies:

Reports of the Comptroller and Auditor General Annual report of UPSC Reports of Finance Commission. Reports of Special officers of SC & ST Report of the National Commission for Scheduled Castes and Scheduled Tribes Report of the National Commission of Backward Classes.

Explanation

Statement 1 is correct: When the central bank buys government securities (like bonds) from the public it injects money into the economy. The sellers of these securities receive cash, increasing the money supply. This is a key tool of monetary policy known as open market operations.

Statement 2 is incorrect: When the public deposits currency into commercial banks, it doesn’t increase the overall money supply. It simply changes the form of money. Currency in circulation decreases but bank deposits increase by the same amount. These deposits can then be used by banks to create credit. Thus the initial act of depositing cash is neutral with respect to the money supply.

Statement 3 is correct: When the government borrows directly from the central bank, it often leads to an increase in the money supply. The central bank essentially creates new money to lend to the government. This is sometimes referred to as "monetizing the debt."

Statement 4 is incorrect: When the Central Bank sells government securities to the public, it effectively reduces the amount of money circulating in the economy. The public (individuals or financial institutions) buys these securities by paying money to the Central Bank. This payment transfers money from the public’s hands to the Central Bank, which essentially "locks away" this cash. This tool is part of Open Market Operations (OMO) aimed at controlling inflation or overheating of the economy.

Explanation

Mixed farming is an agricultural system where crop cultivation and livestock rearing are carried out on the same farm. Mixed farming integrates crop production and animal husbandry, balancing risks while recycling nutrients through manure and crop residues. It diversifies income and enhances sustainability. This practice is designed to maximize the use of available resources and diversify the income sources for the farmer. The integration of crops and animals is a key feature that distinguishes mixed farming from other farming systems.

Option (a) is incorrect: It involves crop diversification typical of commercial farming, not mixed farming with livestock.

Option (b) is incorrect: describes intercropping, which lacks the animal component essential to mixed farming.