UGC NTA NET/JRF Exam, Environmental Sciences, June-2025

Dichlorvos (DDVP): This is a classic Type A organophosphate insecticide. It is direct acting, meaning it does not require metabolic activation to become toxic. It inhibits acetylcholinesterase immediately, leading to accumulation of acetylcholine at synapses.

Malathion: Belongs to Type С organophosphates. Though it is toxic to insects, mammals detoxify it efficiently due to carboxylesterase activity. This makes it relatively safer for humans but still potent as an insecticide.

Parathion: This is a Type B organophosphate insecticide. It is not toxic in its original form but becomes highly toxic once metabolically activated in the liver to paraoxon.

Lindane: Not an organophosphate at all, but an organochlorine insecticide. It acts by interfering with GABAergic neurotransmission, making it distinct from OPs.

E. Radiative Zone: After the Sun's core, this zone transfers energy outward mainly through radiation, where photons undergo countless scatterings before moving ahead.

B. Convection Zone: Energy transport here happens via convection currents of hot plasma. Rising hot gases and sinking cooler ones create turbulent motion.

D. Photosphere: This is the "surface" of the Sun, about 500 km thick, and the layer we directly observe. Sunspots and granules are seen here.

A. Chromosphere: Just above the photosphere, it glows reddish due to strong Ha emission and is best visible during solar eclipses.

C. Corona: The Sun's outermost atmosphere, extending millions of kilometers. It is extremely hot (over a million Kelvin) and gives rise to solar winds.
Thus, from inner to outer: Radiative zone → Convection zone → Photosphere → Chromosphere → Corona.

A. Aqua: Launched in 2002 under NASA's Earth Observing System, it carries MODIS (Moderate Resolution Imaging Spectroradiometer), a multispectral sensor useful for climate and water studies.

B. NOAA satellites: Operational weather satellites carrying VIIRS (Visible Infrared Imaging Radiometer Suite) and AVHRR (Advanced Very High Resolution Radiometer) for meteorological and environmental monitoring.

C. Sentinel-2: A European Space Agency satellite with MSI (Multispectral Instrument), designed for high-resolution land observation, vegetation, soil, and water monitoring.

D. Terra: Another NASA Earth Observing System satellite that carries ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) and MODIS, serving both geological and atmospheric applications.

Atmospheric particles can only exert direct radiative forcing:
This is incorrect because atmospheric aerosols produce both direct and indirect forcing.

Direct forcing → Aerosols scatter and absorb radiation, cooling (sulfates) or warming (black carbon).

Indirect forcing → Aerosols act as cloud condensation nuclei, modifying cloud droplet size, reflectivity (albedo), and lifetime, thus amplifying climate effects.

The other statements are valid:

Combustion of fossil fuels, even complete, releases CO₂, a major greenhouse gas.

Sulfur-derived trace gases (like SO₂) form sulfate aerosols, which cool and counter greenhouse warming.

Polar amplification is a documented phenomenon where warming is stronger in polar regions due to feedbacks like ice-albedo reduction.

Tbilisi Conference (1977): First intergovernmental conference on environmental education, setting global guidelines.

Montreal Protocol (1987): International treaty to phase out ozone-depleting substances like CFCs.

Basel Convention (1989): Regulates transboundary movements of hazardous wastes and their disposal.

Kyoto Protocol (1997): Binding treaty under UNFCCC committing countries to reduce greenhouse gas emissions.

Copenhagen Summit (2009): Part of UN climate change negotiations, though it resulted in a non-binding accord rather than a strong treaty.

Chronological order of enactment: Tbilisi (1977) → Montreal (1987) → Basel (1989) → Kyoto (1997) → Copenhagen (2009).

Nuclear fuel minerals are ores that supply Uranium (U) or Thorium (Th).

Pitchblende (Uraninite): Primary uranium ore → nuclear fuel mineral. Carnotite: Potassium-uranium-vanadate ore → uranium source → nuclear fuel mineral.
Monazite: Rare-earth phosphate containing significant thorium (and some uranium) → nuclear fuel mineral.
Anglesite: Lead sulfate (PbSO⁴), a lead ore with no U/Th not a nuclear fuel mineral.

Task: Convert to µg/m³ at 25 °C, 1 atm (ideal gas).
Formula:

Indian courts routinely invoke the Precautionary Principle in environmental cases to justify prior Environmental Impact Assessment (EIA) and environmental clearance (EC)-i.e., where there is a plausible risk of serious environmental harm, lack of full scientific certainty is not a reason to delay preventive measures.

This underpins the requirement to obtain EC before commencing projects with potential environmental impacts.

Not applicable here:
Caveat Emptor: Buyer-beware doctrine in commerce.
Eminent Domain: State's power to acquire land.
Strict Liability: Liability without fault (used in pollution damage cases), but not the key doctrine for upholding EC requirements under EIA.

CAM plants separate CO₂ uptake and Calvin cycle temporally:
Night (stomata open): CAM plants fix CO₂ via PEP carboxylase to oxaloacetate →malate, stored in vacuoles (malic acid).

Day (stomata closed): Malate is decarboxylated, raising internal CO₂, for the Calvin cycle in chloroplasts while limiting water loss.

Therefore: Separation is temporal (night vs day), not spatial (that's C₄). Claims that CAM is mainly in grasses with daytime-open stomata, or that daytime internal CO₂ is lower than ambient, are incorrect (it's typically higher during decarboxylation).

Exact phrasing of GIM's aim: The Green India Mission under NAPCC is framed to "protect, restore, and enhance" India's forest cover and to respond to climate change through mitigation and adaptation. The triad explicitly used is Protection, Restoration, Enhancement.

Therefore, "Conservation" is NOT one of the three listed aims (even though conservation outcomes naturally result from these activities). Brief on each listed aim:

Protection: Reduce degradation and deforestation; strengthen community/JFM institutions; fire, grazing, and invasive-species management; enforce sustainable harvest.

Restoration: Afforestation/reforestation of degraded/open forests; eco-restoration of vulnerable landscapes and catchments to revive ecosystem function.

Enhancement: Improve forest quality and canopy density; expand tree cover outside forests (farm/agroforestry) to raise ecosystem services and carbon stocks.

Conclusion: Among the given optionsConservation, Enhancement, Protection, Restoration-the term "Conservation" is not the one explicitly listed in the mission's stated aims; the official triad is Protection-RestorationEnhancement.