PYQ Bank — UPSC Civil Services

Statement 1 is correct: guide RNA directs Cas9 to specific DNA sequences for precise editing.

Statement 2 is incorrect: CRISPR-Cas9 can be used in both somatic and germline cells, though germline editing raises ethical concerns.

Statement 3 is correct: CRISPR-Cas9 is derived from bacterial immune mechanisms that bacteria use against viruses.

Therefore, only statements 1 and 3 are correct.

This demonstrates Rayleigh scattering, where shorter wavelengths (blue light) scatter more readily than longer wavelengths.

During the day, blue light is scattered throughout the sky, making it appear blue.

At sunset, light travels through a greater thickness of atmosphere to reach our eyes, causing blue light to scatter away, leaving only the longer wavelengths (red and orange) visible.

Options A, C, and D misunderstand the physical mechanisms involved in light scattering and atmospheric optics.

Option C is incorrect because dark matter has NOT been directly observed or photographed, despite decades of research.

Its existence is inferred through indirect gravitational effects on visible matter and radiation.

Options A, B, and D are all correct: dark matter comprises ~85% of matter in the universe, its existence was inferred from galaxy rotation curves, and it forms halos around galaxies affecting their dynamics.

Dark matter remains one of the greatest unsolved mysteries in physics.

Statements 1, 2, and 3 correctly describe mechanisms of antibiotic resistance: bacteria can enzymatically inactivate antibiotics, acquire resistance genes through horizontal gene transfer from other bacteria, and mutations conferring resistance are selected for under antibiotic pressure.

Statement 4 is incorrect because antibiotic exposure does not directly cause permanent genetic changes; rather, it selects for pre-existing or newly mutated resistant variants.

Understanding these mechanisms is crucial for developing strategies to combat antibiotic resistance, a major global health threat.

Statements 1 and 2 are correct: Aurora Borealis results from solar wind particles channeled by Earth's magnetic field colliding with atmospheric gases, and magnetospheric substorms occur from magnetic reconnection releasing stored energy in the magnetotail.

Statement 3 is incorrect: Van Allen Belts are regions of trapped charged particles (mainly from solar wind and cosmic rays) held by Earth's magnetic field, not formed by cosmic ray concentration due to atmospheric pressure.

The Van Allen Belts are stable radiation zones, not dynamic phenomena caused by atmospheric pressure variations.

Statement 1 is incorrect because India's Ramsar sites are distributed across diverse ecosystems including inland wetlands, coastal areas, and high-altitude wetlands, not just coastal regions.

Statement 2 is correct as the Ramsar Convention mandates that contracting parties formulate and implement their national wetland policies and strategies.

Statement 3 is correct as both Chilika Lake (Odisha) and Loktak Lake (Manipur) are designated Ramsar sites of international importance.

Therefore, only statements 2 and 3 are correct.

Ecological debt refers to the historical responsibility and obligation of developed nations due to their disproportionate consumption of global resources and emission of greenhouse gases since industrialization, which has degraded the global environment.

This concept acknowledges that developed nations owe a debt to developing nations for the environmental damage caused.

Option A refers to conservation obligations, Option C refers to economic costs of environmental measures, and Option D describes ecological footprint—none of which capture the essence of ecological debt.

The concept is central to climate justice discussions and frames environmental accountability in terms of historical responsibility.

Statement 1 is correct—the NAPCC identifies eight core national missions including missions on solar energy, enhanced energy efficiency, sustainable agriculture, water conservation, and others.

Statement 2 is incorrect as the Pradhan Mantri Khanij Shram Kalyan Yojana is a social security scheme for mine workers, not one of the NAPCC missions.

Statement 3 is correct as the National Mission for Sustainable Agriculture (NMSA) is one of the eight core missions explicitly addressing agricultural sustainability and water management.

The NAPCC was approved in 2008 and serves as India's comprehensive climate change policy framework.

Phenological mismatch refers to the disruption in synchronization between the timing of life cycle events of interdependent species caused by differential responses to environmental cues, particularly climate change.

For example, if plants flower earlier due to warming but their pollinators emerge later, the mismatch can reduce successful reproduction.

This has cascading effects on food webs and ecosystem functioning.

Option A describes phenotypic plasticity limitations, Option C describes reproductive isolation, and Option D describes spatial genetic differentiation—none of which address the temporal desynchronization that defines phenological mismatch.

This concept is crucial in understanding climate change impacts on ecosystems.

Statement 1 is incorrect because Reserved Forests, while protected, do allow some regulated extractive activities like timber harvesting and non-timber forest product collection under management plans, unlike National Parks which prohibit extractive use.

Statement 2 is correct as the Wildlife Protection Act, 1972 establishes these three categories of Protected Areas with varying levels of protection.

Statement 3 is correct as Community Forests and Community Reserves represent participatory forest management where local communities have significant roles in management and benefit-sharing.

Therefore, statements 2 and 3 are correct, reflecting India's multi-layered conservation approach combining state protection with community participation.