Q120. Which was the most recently designated Indian biosphere reserve among these options?
[WBCS Mains – Environmental Science (2023)]
(A) Nilgiri
(B) Andaman and Nicobar
(C) Gulf of Mannar
(D) Panna
Answer: (D) Panna
Explanation: Panna was designated as a biosphere reserve in 2011, later than Nilgiri, Gulf of Mannar and Great Nicobar. UNESCO subsequently recognised Panna in its World Network of Biosphere Reserves in 2020.
Q119. How many notified biosphere reserves did India have in 2023?
[WBCS Mains – Environmental Science (2023)]
(A) 17
(B) 18
(C) 19
(D) 20
Answer: (B) 18
Explanation: India had 18 nationally designated biosphere reserves in 2023. This total differs from the smaller number included in UNESCO’s World Network, so the wording of a question about national versus international recognition matters.
Q118. Gahirmatha Marine Sanctuary in Odisha is especially associated with protecting:
[WBCS Mains – Environmental Science (2023)]
(A) Sea turtles
(B) Crocodiles alone
(C) Elephants
(D) Deer
Answer: (A) Sea turtles
Explanation: Gahirmatha is globally known for mass nesting of Olive Ridley sea turtles along the Odisha coast. Conservation measures focus on nesting beaches, marine habitats and fishing restrictions that reduce accidental turtle mortality.
Q117. What is the maximum height of the troposphere among the following options?
[WBCS Mains – Environmental Science (2023)]
(A) 10 km
(B) 12 km
(C) 14.5 km
(D) 16.8 km
Answer: (D) 16.8 km
Explanation: The troposphere is thickest over the warm equatorial region, extending to around 16–18 kilometres, and much thinner near the poles. Most ordinary weather systems occur within this lowest atmospheric layer.
Q116. Using living organisms to break down environmental pollutants is known as:
[WBCS Mains – Environmental Science (2023)]
(A) Microremediation
(B) Nanoremediation
(C) Bioremediation
(D) All of the above
Answer: (C) Bioremediation
Explanation: Bioremediation uses microorganisms, plants or their biological processes to detoxify or remove contaminants from soil and water. Examples include bacterial breakdown of petroleum hydrocarbons and microbial treatment of organic wastewater.
Q115. Who formulated the competitive exclusion principle?
[WBCS Mains – Environmental Science (2023)]
(A) Darwin
(B) Gause
(C) Lamarck
(D) Odum
Answer: (B) Gause
Explanation: Gause demonstrated that two species competing for exactly the same limiting resource cannot coexist indefinitely under unchanging conditions. They may persist through niche differentiation, resource partitioning or environmental variation.
Q114. Chandraprabha Wildlife Sanctuary is situated in which district of Uttar Pradesh?
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Sonbhadra
(B) Chandauli
(C) Bahraich
(D) Lakhimpur Kheri
Answer: (B) Chandauli
Explanation: Chandraprabha Wildlife Sanctuary lies in Chandauli district in eastern Uttar Pradesh. Known for forest habitats and waterfalls, it also featured an unsuccessful historical attempt to introduce Asiatic lions.
Q113. Which factor most strongly contributes to contemporary biodiversity loss?
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Genetic assimilation
(B) Predator control alone
(C) Destruction of natural habitats
(D) Pest control alone
Answer: (C) Destruction of natural habitats
Explanation: Habitat destruction and fragmentation eliminate breeding sites, food sources and corridors used by many organisms. Though pollution and invasive species also matter, habitat loss is a major direct driver of biodiversity decline.
Q112. Where is India’s first National Centre for Marine Biodiversity situated?
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) Mumbai
(B) Jamnagar
(C) Bhavnagar
(D) Puducherry
Answer: (B) Jamnagar
Explanation: The National Centre for Marine Biodiversity is associated with Jamnagar in Gujarat, close to rich coastal and marine habitats. It supports research, management and capacity building for conservation of marine biodiversity.
Q111. In a national park, genetic diversity is maintained primarily through:
[UPPSC PCS Prelims – GS Paper I (2023)]
(A) In-situ conservation
(B) Ex-situ conservation
(C) Gene pool as a stand-alone method
(D) None of these
Answer: (A) In-situ conservation
Explanation: National parks safeguard interacting wild populations in their natural environment. This in-situ approach maintains habitat, ecological processes and the potential for natural reproduction and genetic exchange among individuals.
