In India's Western Coastal regions, which of the following represents a keystone species in mangrove ecosystems?
Answer: A
Crabs in mangrove ecosystems regulate sediment composition and nutrient cycling, disproportionately affecting ecosystem structure.
Q.442Medium
Which of the following is NOT a density-dependent factor affecting population growth?
Answer: C
Earthquakes are density-independent factors. Density-dependent factors (competition, parasitism, disease) increase with population density.
Q.443Easy
What is the primary reason for the formation of the ozone hole over Antarctica?
Answer: B
CFCs (chlorofluorocarbons) release chlorine atoms that catalytically destroy ozone molecules in the stratosphere.
Q.444Easy
Which of the following adaptations would be most beneficial for desert animals in the Thar Desert?
Answer: B
Desert animals like jerboas exhibit nocturnal behavior and have efficient kidneys to conserve water, reducing evaporative loss.
Q.445Medium
In the carbon cycle, which process is primarily responsible for returning carbon dioxide to the atmosphere in terrestrial ecosystems?
Answer: D
Both cellular respiration by organisms and decomposition of dead organic matter release CO2 back into the atmosphere.
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Q.446Easy
Which of the following would represent the highest biodiversity hotspot in India?
Answer: B
Western Ghats and Northeast India are recognized global biodiversity hotspots with high endemism and species richness.
Q.447Hard
In a pyramid of numbers, why would an inverted pyramid occur in certain ecosystems?
Answer: A
Inverted pyramids occur when individual organisms at lower trophic levels are larger (e.g., one tree supporting many insects).
Q.448Hard
Which of the following statements about ecological pyramids is correct?
Answer: D
Energy pyramids always show decreasing energy upward and cannot be inverted, making them the most reliable representation.
Q.449Medium
Which mechanism would best explain the survival of antibiotic-resistant bacteria in hospital environments?
Answer: B
Antibiotic-resistant strains survive and proliferate while susceptible strains are eliminated, exemplifying natural selection.
Q.450Medium
In India's Sundarbans, the Bengal tiger population is threatened primarily by habitat loss due to:
Answer: B
Sundarbans face threats from climate change-induced sea level rise and human encroachment, reducing tiger habitat.
Q.451Medium
Which of the following is an example of resource partitioning in nature?
Answer: B
Resource partitioning reduces competition by allowing species to utilize different niches (feeding at different heights).
Q.452Hard
Which of the following would be the most effective long-term solution for controlling invasive species in Indian wetlands?
Answer: B
Biological control using natural enemies provides sustainable, long-term management without ecological disruption.
Q.453Medium
Which of the following best explains the concept of ecological resilience?
Answer: B
Ecological resilience is the capacity to recover from disturbances and return to equilibrium state.
Q.454Hard
In the context of India's National Action Plan on Climate Change, which sector is projected to face the most severe water stress by 2050?
Answer: B
Agriculture accounts for ~70% of water use in India and will face severe stress due to changing precipitation patterns and increased evapotranspiration.
Q.455Easy
Which of the following organisms would have the shortest lifespan in a temperate forest ecosystem?
Answer: A
Decomposer bacteria have generation times measured in hours to days, making them have the shortest lifespan compared to other organisms in the ecosystem.
Q.456Medium
In the Western Ghats biodiversity hotspot, what percentage of plant species are endemic to India?
Answer: B
The Western Ghats contains about 60% endemic plant species, making it one of India's most critical biodiversity areas.
Q.457Easy
Which succession type occurs on newly formed volcanic islands like those in the Indian Ocean?
Answer: B
Primary succession occurs on bare, lifeless substrates where no soil exists, such as newly formed volcanic islands.
Q.458Medium
According to India's National Green Tribunal (NGT) 2024 decisions, which industrial effluent poses the greatest threat to the Yamuna River ecosystem?
Answer: B
Leather tanning wastes contain high concentrations of chromium and other heavy metals that severely degrade aquatic ecosystems.
Q.459Medium
In a forest biome, if 1000 kg of plant biomass is available at the producer level, approximately how much energy would be available at the secondary consumer level (assuming 10% energy transfer)?
Answer: B
Following the 10% law: Producers (1000 kg) → Primary consumers (100 kg) → Secondary consumers (10 kg).
Q.460Easy
Which biotic potential would be highest for a species in ideal laboratory conditions?
Answer: B
Intrinsic rate of increase (biotic potential) is expressed as λ and represents maximum reproductive capacity under ideal conditions.
