Q110. Biochemical Oxygen Demand (BOD) is a standard criterion for measuring:
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Pollution in aquatic ecosystems
(B) Oxygen at high altitude
(C) Oxygen in human blood
(D) Oxygen in forest ecosystems
Answer: (A) Pollution in aquatic ecosystems
Explanation: BOD measures the oxygen used by microorganisms to decompose biodegradable matter in a water sample. Higher readings generally point to greater organic pollution and increased risk of oxygen depletion.
Q109. Which is an example of a lotic ecosystem?
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Swamp
(B) Pond
(C) River
(D) Marsh
Answer: (C) River
Explanation: A river is a lotic system because its water flows continuously. Ponds and many swamps represent standing-water conditions, commonly described as lentic, although their hydrology can vary by location.
Q108. Trophic levels in an ecosystem are defined by:
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Organisms connected in a food chain
(B) Plants alone
(C) All animals together
(D) Only carnivores
Answer: (A) Organisms connected in a food chain
Explanation: Trophic levels group organisms according to how they obtain energy in feeding relationships. Producers form the first level, followed by primary and higher-order consumers and associated decomposer pathways.
Q107. In which atmospheric layer is the ultraviolet-absorbing ozone layer concentrated?
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Troposphere
(B) Mesosphere
(C) Stratosphere
(D) Thermosphere
Answer: (C) Stratosphere
Explanation: The ozone layer is concentrated in the stratosphere, where ozone absorbs much of the incoming harmful ultraviolet radiation. Surface-level ozone, by contrast, is a pollutant that can damage lungs and crops.
Q106. In Jharkhand, soil pollution is mainly attributed to:
[JPSC CCE Prelims – GS Paper II (2023)]
(A) Excess rainfall
(B) Forest growth
(C) Industrial waste and mining residues
(D) Natural erosion alone
Answer: (C) Industrial waste and mining residues
Explanation: Jharkhand’s mining and industrial activities generate tailings, fly ash and other waste that can contaminate surrounding soil. Inadequate disposal and heavy-metal exposure create risks for agriculture, groundwater and people.
Q105. India enacted the Biological Diversity Act in which year?
[JPSC CCE Prelims – GS Paper II (2023)]
(A) 1992
(B) 2002
(C) 2006
(D) 2010
Answer: (B) 2002
Explanation: The Biological Diversity Act was enacted in 2002 to support conservation, sustainable use and equitable sharing of benefits from biological resources. It implements key commitments associated with the Convention on Biological Diversity.
Q104. Which Jharkhand district faces serious subsidence problems from coal mining?
[JPSC CCE Prelims – GS Paper II (2023)]
(A) Hazaribag
(B) Dhanbad
(C) Rajmahal
(D) Lohardaga
Answer: (B) Dhanbad
Explanation: Dhanbad includes the Jharia coalfield, where underground fires and extensive mining contribute to land subsidence. These hazards affect settlements, transport infrastructure and the surrounding environment.
Q103. Which of these constitutes climate change mitigation?
[JPSC CCE Prelims – GS Paper II (2023)]
(A) Increasing fossil fuel consumption
(B) Afforestation and carbon sequestration
(C) Expanding coal mines
(D) Increasing industrial emissions
Answer: (B) Afforestation and carbon sequestration
Explanation: Afforestation adds vegetation capable of storing carbon, while carbon sequestration reduces atmospheric carbon dioxide. Expanding fossil-fuel use and emissions instead raises the greenhouse-gas burden.
Q102. Assertion: Climate change affects Jharkhand agriculture.
Reason: Irregular monsoons and droughts alter crop growth.
[JPSC CCE Prelims – GS Paper II (2023)]
(A) Both true; reason explains assertion
(B) Both true; reason does not explain
(C) Assertion true; reason false
(D) Assertion false; reason true
Answer: (A) Both true; reason explains assertion
Explanation: Agriculture in Jharkhand relies heavily on seasonal rainfall. Increasing monsoon variability and drought conditions can reduce sowing opportunities, yields and crop reliability, directly explaining the assertion.
Q101. Which constitutional article directs the State to protect the environment, forests and wildlife?
[JPSC CCE Prelims – GS Paper II (2023)]
(A) Article 48A
(B) Article 48B
(C) Article 48C
(D) Article 49A
Answer: (A) Article 48A
Explanation: Article 48A, added through the Forty-second Amendment, directs the State to protect and improve the environment and safeguard forests and wildlife. Citizens also have an environmental duty under Article 51A(g).
