I85PREP
⌘ K
Odisha BSE HSC Env & Pop Ed study materials
Odisha BSE HSC Env & Pop Ed study resources

Odisha BSE HSC Env & Pop Ed practice questions

One question at a time. Build your Odisha BSE HSC Env & Pop Ed understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Ecosystems and Environmental Components

In the study of ecosystems, what term describes the non-living physical and chemical factors such as sunlight, temperature, water and soil that surround organisms?

  1. Trophic levels
  2. Abiotic components Correct answer.
  3. Decomposer community
  4. Biotic components

Explanation

Abiotic components are the non-living parts of an ecosystem, including light, heat, water, air, soil and minerals. They set the physical limits within which living organisms function. Biotic components refer instead to the living members of the ecosystem.

Question 2Ecosystems and Environmental Components

Green plants that manufacture their own food from carbon dioxide and water using sunlight are best described as which of the following?

  1. Producers Correct answer.
  2. Tertiary consumers
  3. Decomposers
  4. Primary consumers

Explanation

Producers, also called autotrophs, synthesise organic food from inorganic raw materials using energy from sunlight. They form the base of every food chain. Consumers and decomposers depend on the organic matter that producers create.

Question 3Ecosystems and Environmental Components

In a pond ecosystem, mosquito larvae, small fish and frogs occupy different feeding positions. Which term refers to the specific place where an organism lives within that pond?

  1. Niche
  2. Habitat Correct answer.
  3. Population
  4. Biome

Explanation

A habitat is the physical place or environment in which an organism lives, such as the shallow weedy margin of a pond. A niche, by contrast, describes the organism's functional role and its full range of resource use. The two concepts are related but not identical.

Question 4Ecosystems and Environmental Components

Which of the following sequences correctly represents the flow of energy in a grazing food chain?

  1. Sun → grass → frog → grasshopper → snake
  2. Grass → sun → grasshopper → frog → snake
  3. Sun → grasshopper → grass → frog → snake
  4. Sun → grass → grasshopper → frog → snake Correct answer.

Explanation

Energy enters the ecosystem as sunlight and is captured by producers such as grass. It then passes to herbivores (grasshopper) and subsequently to carnivores (frog, then snake). Each transfer moves energy from one trophic level to the next.

Question 5Ecosystems and Environmental Components

Organisms such as fungi and bacteria that break down dead leaves and animal remains into simpler substances are known as which of the following?

  1. Herbivores
  2. Producers
  3. Carnivores
  4. Decomposers Correct answer.

Explanation

Decomposers are organisms that break down complex organic matter in dead bodies and wastes into simpler inorganic substances. This releases nutrients such as nitrogen and phosphorus back to the soil or water for reuse by producers. They are essential for nutrient cycling.

Question 6Ecosystems and Environmental Components

Which of the following is a correct example of a natural terrestrial ecosystem found in Odisha?

  1. A fish hatchery tank
  2. Similipal forest Correct answer.
  3. A paddy field
  4. A cement factory

Explanation

A natural terrestrial ecosystem is one that has developed largely without deliberate human management on land. The Similipal forest is a natural forest ecosystem with its own producers, consumers and decomposers. Factories, hatchery tanks and cultivated paddy fields are man-made or heavily managed systems.

Question 7Ecosystems and Environmental Components

Which of the following pairs correctly matches an ecosystem with its most characteristic physical feature?

  1. Grassland ecosystem - permanently waterlogged soil
  2. Mangrove ecosystem - salt-tolerant trees in tidal coastal mud Correct answer.
  3. Coral reef ecosystem - dry sandy dunes
  4. Desert ecosystem - dense evergreen canopy

Explanation

Mangroves are salt-tolerant trees with breathing roots that grow in tidal mud along sheltered coasts, such as parts of coastal Odisha. Each ecosystem type is defined by the physical conditions to which its organisms are adapted. The other pairs describe features that do not belong to those ecosystems.

Question 8Ecosystems and Environmental Components

In an ecosystem, the total energy available at each trophic level decreases sharply as it passes to the next level. What is the main reason for this decrease?

  1. Energy is converted into soil minerals at each level
  2. Much energy is lost as heat during respiration and in waste at each level Correct answer.
  3. Producers absorb almost all the energy that consumers release
  4. Carnivores create new energy to replace what is lost

Explanation

At every trophic level organisms use part of their energy for respiration, which releases heat, and pass some out as waste or uneaten parts. Only a small fraction is stored as new biomass available to the next level. Energy therefore cannot be recycled and must flow one way through the ecosystem.

Question 9Ecosystems and Environmental Components

A food web in a grassland shows grass eaten by grasshoppers and by mice; mice are eaten by owls, and grasshoppers by frogs. Which statement best explains why a food web is more realistic than a single food chain?

  1. A food chain includes decomposers while a food web excludes them
  2. A food web shows only producers and decomposers
  3. Most consumers feed on more than one species, so feeding links branch and interconnect Correct answer.
  4. A food web removes the need for trophic levels

Explanation

In nature most organisms eat several kinds of food and are eaten by several predators, so feeding relationships form a branching network. A food web captures these multiple, interlinked pathways. A single chain oversimplifies by showing only one route of energy flow.

Question 10Ecosystems and Environmental Components

In the nitrogen cycle, which group of microorganisms converts atmospheric nitrogen gas into ammonia compounds usable by plants?

  1. Photosynthetic green algae
  2. Nitrifying bacteria that convert nitrite to nitrate
  3. Nitrogen-fixing bacteria such as those in root nodules of legumes Correct answer.
  4. Denitrifying bacteria

Explanation

Nitrogen fixation is the conversion of inert atmospheric nitrogen gas into ammonia or related compounds that plants can use. It is carried out by free-living and symbiotic bacteria, for example those in the root nodules of pulses. Other bacteria act at different steps of the cycle.

Question 11Ecosystems and Environmental Components

During the carbon cycle, which two processes mainly move carbon from the atmosphere into living biomass and back again?

  1. Transpiration removes carbon dioxide; condensation returns it
  2. Photosynthesis removes carbon dioxide; respiration returns it to the atmosphere Correct answer.
  3. Nitrogen fixation removes carbon; denitrification returns it
  4. Respiration removes carbon dioxide; photosynthesis returns it

Explanation

Photosynthesis uses atmospheric carbon dioxide to build organic compounds in producers. Respiration by living organisms, including plants, oxidises these compounds and releases carbon dioxide back. These two complementary processes form the core of the biological carbon cycle.

Question 12Ecosystems and Environmental Components

In an ecosystem, which of the following best describes the relationship between gross primary productivity and net primary productivity?

  1. Gross primary productivity is the energy stored by consumers in their bodies
  2. Net primary productivity is always greater than gross primary productivity
  3. Gross primary productivity equals net primary productivity plus energy lost by consumers
  4. Net primary productivity equals gross primary productivity minus energy used in plant respiration Correct answer.

Explanation

Gross primary productivity is the total energy fixed by producers through photosynthesis. Plants themselves respire and use part of this energy, so net primary productivity is the remainder stored as new plant biomass. This stored energy is what herbivores can consume.

Question 13Ecosystems and Environmental Components

Which of the following human activities would most directly reduce the biotic components of a forest ecosystem?

  1. Marking a boundary line on a map
  2. Recording rainfall in the forest
  3. Large-scale felling of trees Correct answer.
  4. Measuring the height of trees

Explanation

Biotic components are the living organisms of an ecosystem. Large-scale felling removes producers and destroys the habitats of animals and microbes, directly reducing the living community. Measuring, recording and mapping are observational activities that do not remove organisms.

Question 14Ecosystems and Environmental Components

In an aquatic ecosystem, a layer of algae growing rapidly on the surface after a heavy input of fertiliser blocks sunlight to submerged plants. Which interpretation is most reasonable?

  1. Excess nutrients cause algal blooms that shade submerged producers and disrupt the ecosystem Correct answer.
  2. Fertiliser input has no effect on aquatic producers
  3. The algae add oxygen and improve conditions for submerged plants
  4. Light is not needed by submerged plants

Explanation

Fertiliser runoff adds nutrients such as nitrates and phosphates, which can trigger rapid algal growth called a bloom. The floating algae intercept sunlight, so submerged plants lose the light they need for photosynthesis. Their decline can then affect the animals that depend on them.

Question 15Ecosystems and Environmental Components

A student lists the following for a pond: water temperature, dissolved oxygen, tadpoles, Hydrilla plants, bacteria in mud. Which grouping correctly separates abiotic from biotic components?

  1. Abiotic: tadpoles and Hydrilla; Biotic: temperature and dissolved oxygen
  2. Abiotic: dissolved oxygen and bacteria; Biotic: temperature and tadpoles
  3. Abiotic: temperature, Hydrilla and bacteria; Biotic: dissolved oxygen and tadpoles
  4. Abiotic: temperature and dissolved oxygen; Biotic: tadpoles, Hydrilla and bacteria Correct answer.

Explanation

Temperature and dissolved oxygen are physical and chemical conditions, so they are abiotic. Tadpoles, Hydrilla and bacteria are living organisms, so they are biotic. Correct classification depends on whether the item is a non-living factor or a living organism.

Question 16Ecosystems and Environmental Components

An ecologist notes that two species of insect in the same grassland feed on the same grass species at the same height. Which conclusion best follows from this observation?

  1. They occupy two completely separate niches with no interaction
  2. One must be a decomposer and the other a producer
  3. Their niches overlap and they may compete for the same resource Correct answer.
  4. They must belong to different trophic levels

Explanation

A niche includes the resources an organism uses and how it uses them. Two species feeding on the same food at the same place have overlapping niches and therefore compete. Competition may lead to one species being excluded or to a shift in resource use.

Question 17Ecosystems and Environmental Components

Which statement correctly explains why decomposers are essential for the long-term sustainability of a terrestrial ecosystem?

  1. They increase the total energy entering the ecosystem
  2. They prevent any energy from being lost as heat
  3. They release mineral nutrients from dead matter so producers can reuse them Correct answer.
  4. They convert sunlight directly into food for consumers

Explanation

Decomposers break down dead organic material and release mineral nutrients such as nitrates and phosphates into the soil. Producers can then absorb and reuse these nutrients, keeping material cycling. Without decomposition, nutrients would remain locked in dead matter.

Question 18Ecosystems and Environmental Components

In a marine food chain, phytoplankton are eaten by zooplankton, which are eaten by small fish, which are eaten by large fish. If the phytoplankton fix 10,000 units of energy, approximately how much energy is available at the small fish level under the ten per cent rule?

  1. 100 units Correct answer.
  2. 1,000 units
  3. 10 units
  4. 10,000 units

Explanation

Under the ten per cent rule about one-tenth of the energy at one trophic level is transferred to the next. Phytoplankton to zooplankton gives about 1,000 units, and zooplankton to small fish gives about 100 units. Each transfer therefore reduces the energy available.

Question 19Ecosystems and Environmental Components

Which of the following best explains why a food chain rarely has more than four or five trophic levels?

  1. Producers refuse to be eaten beyond the third level
  2. So little energy remains after repeated transfers that higher levels cannot be supported Correct answer.
  3. Top predators are always producers
  4. Decomposers remove all energy before the fourth level

Explanation

Because only about one-tenth of the energy passes to each successive level, the energy remaining after several transfers becomes too small to support another level. The length of a chain is thus limited by energy availability. This is why very high trophic levels are rare.

Question 20Ecosystems and Environmental Components

In a mangrove ecosystem, the roots trap sediment, reduce wave action and provide nursery habitat for fish. This illustrates which concept?

  1. Biological magnification of a pesticide
  2. Trophic cascade caused by a keystone predator
  3. Primary succession on bare rock
  4. Ecosystem services provided by a natural community Correct answer.

Explanation

Ecosystem services are the benefits that natural communities provide to people and to other organisms. Sediment trapping, coastal protection and nursery habitat are functions of the mangrove community. They arise from the physical and biological structure of the ecosystem itself.

Question 21Ecosystems and Environmental Components

A pond is found to have very low dissolved oxygen despite abundant algae, and dead fish are observed. Which sequence of events most plausibly explains this?

  1. Algal decay → nutrient enrichment → algal bloom → oxygen depletion
  2. Nutrient enrichment → algal bloom → algal decay by bacteria → oxygen depletion Correct answer.
  3. Nutrient enrichment → oxygen depletion → algal decay → algal bloom
  4. Oxygen depletion → algal bloom → nutrient enrichment → algal decay

Explanation

Nutrient enrichment first stimulates a dense algal bloom. When the algae die, aerobic bacteria decompose them and consume large amounts of dissolved oxygen. The resulting oxygen depletion, not the algae themselves, kills fish and other animals.

Question 22Ecosystems and Environmental Components

Which statement best distinguishes nutrient cycling from energy flow in an ecosystem?

  1. Nutrients are recycled between organisms and the environment, while energy flows one way and is lost as heat Correct answer.
  2. Energy is recycled through decomposers while nutrients are lost as heat
  3. Both nutrients and energy are recycled indefinitely without loss
  4. Nutrients flow one way while energy is recycled through the food web

Explanation

Matter such as carbon, nitrogen and phosphorus is repeatedly reused as it passes between organisms and the physical environment. Energy, in contrast, enters as sunlight and leaves as heat at each transfer, so it is not recycled. This difference is fundamental to ecosystem function.

Question 23Ecosystems and Environmental Components

In the phosphorus cycle, phosphorus has no significant gaseous phase. Which consequence follows most directly from this fact?

  1. Phosphorus cycles mainly through soil, water and organisms rather than through the atmosphere Correct answer.
  2. Phosphorus is fixed from the air by root-nodule bacteria
  3. Phosphorus is not needed by living organisms
  4. Phosphorus escapes rapidly as a gas during respiration

Explanation

Because phosphorus lacks a major atmospheric reservoir, its cycle is sedimentary: it moves between rocks, soil, water and organisms. Weathering releases phosphate, which producers absorb and consumers pass along. Decomposers return it to the soil and water.

Question 24Ecosystems and Environmental Components

Which of the following correctly describes the role of a keystone species in an ecosystem?

  1. It is always the most abundant species in the ecosystem
  2. It has no interaction with other species
  3. Its removal causes disproportionately large changes in the structure of the community Correct answer.
  4. It is always a producer at the first trophic level

Explanation

A keystone species has an influence on community structure that is large relative to its abundance. Removing it can trigger major changes, such as the loss of other species or alteration of habitat. Its importance comes from its ecological role, not from being the most numerous organism.

Question 25Ecosystems and Environmental Components

A farmer notices that a field left uncultivated for several years gradually develops grasses, then shrubs and finally small trees. Which ecological process is being described?

  1. Nitrogen fixation
  2. Eutrophication
  3. Ecological succession Correct answer.
  4. Biological magnification

Explanation

Ecological succession is the orderly, gradual replacement of one community by another over time at the same site. Abandoned fields typically pass from grasses to shrubs and then to trees. Each stage modifies conditions such as soil and light, favouring the next.

Question 26Ecosystems and Environmental Components

In the study of ecosystems, which term refers to all the living organisms interacting with one another in a given area, together with the non-living surroundings they exchange materials with?

  1. Ecosystem Correct answer.
  2. Population
  3. Biome
  4. Community

Explanation

An ecosystem is the functional unit formed by a biological community plus its physical environment, with continuous exchange of energy and matter between the living and non-living parts. A community lacks the abiotic component, a population covers only one species, and a biome is a much larger climatic region containing many ecosystems.

Question 27Ecosystems and Environmental Components

Which of the following is an abiotic component of a rice-field ecosystem in Odisha?

  1. Tadpoles swimming between the seedlings
  2. Nitrogen-fixing cyanobacteria in the floodwater
  3. Stem-borer larvae inside the paddy stem
  4. Waterlogged soil with low oxygen content Correct answer.

Explanation

Abiotic components are the non-living physical and chemical factors of an ecosystem, such as soil, water, temperature, light and dissolved gases. Waterlogged soil with low oxygen is a physical and chemical condition of the habitat, whereas cyanobacteria, tadpoles and insect larvae are all living organisms and therefore biotic.

Question 28Ecosystems and Environmental Components

In a grazing food chain, herbivores are placed at which trophic level, and why?

  1. First trophic level, because they are the most numerous organisms
  2. Fourth trophic level, because they occupy the top of the chain
  3. Third trophic level, because they also consume other animals
  4. Second trophic level, because they obtain energy directly from producers Correct answer.

Explanation

The trophic level of an organism is fixed by the number of energy-transfer steps between it and the producer. Producers such as grasses form the first trophic level, so herbivores that feed directly on them occupy the second trophic level regardless of their abundance or size.

Question 29Ecosystems and Environmental Components

Two species of birds in a wetland both feed on the same small fish at the same time of day. Which ecological interaction does this situation describe, and what is its likely consequence?

  1. Parasitism, so one species gradually weakens the other
  2. Commensalism, so one species gains while the other is unaffected
  3. Mutualism, so both species benefit and their populations grow faster
  4. Competition, so one species may be excluded or shift its feeding niche Correct answer.

Explanation

When two species require the same limited resource in the same place and time, they are in competition, since each reduces the food available to the other. This pressure can lead to competitive exclusion of one species or to resource partitioning, in which one species shifts its feeding time, prey size or habitat.

Question 30Ecosystems and Environmental Components

A mangrove swamp in coastal Odisha receives large inputs of leaf litter and dead organic matter. Which statement best explains why such an ecosystem can support a large detritus food chain alongside its grazing chain?

  1. Detritus chains operate only in freshwater, so the mangrove example cannot support one
  2. Detritus contains no energy, so the detritus chain survives only on sunlight captured by the decomposers
  3. Detritus is rich in stored chemical energy, so decomposers and detritivores release it gradually to many consumers Correct answer.
  4. Detritus is converted directly into new solar energy by the bacteria that break it down

Explanation

Dead organic matter still holds chemical energy captured earlier by producers, and decomposers plus detritivores such as crabs, worms and molluscs feed on it and are themselves eaten by fish and birds. This makes the detritus pathway a major route of energy transfer in mangroves, often exceeding the grazing chain in such systems.

Question 31Natural Resources and Conservation

Which of the following is classified as a renewable natural resource in the Odisha HSC Environmental and Population Education syllabus?

  1. Iron ore mined in Keonjhar district
  2. Coal from the Talcher coalfield
  3. Petroleum pumped from offshore wells
  4. Wind energy used for power generation Correct answer.

Explanation

Renewable resources can be naturally replenished within a human timescale, and wind is continuously generated by atmospheric processes. Coal, petroleum and iron ore form over millions of years and are consumed far faster than they regenerate, so they are non-renewable.

Question 32Natural Resources and Conservation

In the context of resource classification, groundwater drawn from an aquifer faster than rainfall recharges it is best described as:

  1. A potential resource
  2. An inexhaustible resource
  3. A perpetual resource
  4. A renewable resource under stress Correct answer.

Explanation

Groundwater is technically renewable because it is replenished by infiltration and percolation of rain. However, when extraction exceeds the recharge rate, the resource is being depleted faster than nature restores it, so it is renewable but under stress.

Question 33Natural Resources and Conservation

Which soil conservation measure is most appropriate for reducing soil erosion on steep sloping farmland in the hilly regions of Odisha?

  1. Flood irrigation of the field throughout the year
  2. Removal of all vegetation from field borders
  3. Construction of contour bunds and terracing Correct answer.
  4. Deep ploughing along the slope direction

Explanation

Contour bunds and terraces break the length of the slope, slow down runoff and trap soil carried by water. Ploughing downslope accelerates rill erosion, and removing vegetation destroys the root binding that holds soil in place.

Question 34Natural Resources and Conservation

Deforestation in the catchment of a river typically leads to which sequence of effects?

  1. Increased surface runoff, greater soil erosion, faster siltation of reservoirs Correct answer.
  2. Reduced runoff, higher infiltration, lower flood peaks
  3. Higher transpiration, increased rainfall, reduced flood risk
  4. Increased infiltration, higher groundwater table, reduced siltation

Explanation

Tree roots and leaf litter promote infiltration and slow runoff. When forests are cleared, rainwater runs off the surface rapidly, carrying soil into streams and causing reservoirs to silt up sooner.

Question 35Natural Resources and Conservation

Which of the following best explains why biodiversity conservation is important for sustaining natural resources?

  1. It maintains ecosystem stability and the services on which resource use depends Correct answer.
  2. It guarantees that no species will ever become extinct
  3. It removes the need for soil and water conservation measures
  4. It permanently increases the total rainfall of a region

Explanation

Biodiversity underpins ecosystem functions such as pollination, nutrient cycling and pest control, which support agriculture, forestry and fisheries. Conserving it keeps these services and the resource base stable over time.

Question 36Natural Resources and Conservation

A farmer in coastal Odisha plants casuarina trees along the shoreline to protect fields from cyclonic storms. This practice is an example of:

  1. Terrace farming for slope management
  2. Shelterbelt plantation for coastal protection Correct answer.
  3. Contour ploughing for moisture retention
  4. Crop rotation for soil fertility

Explanation

Shelterbelts are belts of trees planted to reduce wind speed and protect land from wind and storm damage. Coastal shelterbelts such as casuarina reduce the impact of cyclonic winds and check sand drift.

Question 37Natural Resources and Conservation

Which of the following is a non-conventional source of energy that can be harnessed in rural Odisha for cooking and lighting?

  1. Kerosene
  2. Diesel
  3. Bituminous coal
  4. Biogas from cattle dung Correct answer.

Explanation

Biogas produced by anaerobic digestion of cattle dung is a non-conventional, renewable energy source suited to rural households. It provides clean fuel for cooking and can generate electricity or light for homes.

Question 38Natural Resources and Conservation

The main environmental advantage of using solar photovoltaic panels for rural electrification is that they:

  1. Produce power continuously through the night
  2. Eliminate the need for any storage or maintenance
  3. Require no land area for installation
  4. Generate electricity without emitting greenhouse gases during operation Correct answer.

Explanation

Solar panels convert sunlight directly into electricity without combustion, so they produce no greenhouse gas emissions while running. Their output is limited to daylight hours and they still need land, storage and maintenance.

Question 39Natural Resources and Conservation

Which practice represents sustainable use of forest resources?

  1. Clear-felling a hillside for a single season of cultivation
  2. Selective felling with replanting of harvested species Correct answer.
  3. Burning forest undergrowth to clear land for grazing
  4. Harvesting timber faster than natural regeneration

Explanation

Selective felling removes only mature trees and replanting restores the harvested stock, so the forest keeps regenerating. Clear-felling, burning and over-harvesting all deplete the resource faster than it can recover.

Question 40Natural Resources and Conservation

In the context of the hydrological cycle, which process returns water vapour from plants to the atmosphere?

  1. Transpiration Correct answer.
  2. Infiltration
  3. Condensation
  4. Precipitation

Explanation

Transpiration is the loss of water vapour from plant leaves through stomata, and together with evaporation it forms the evapotranspiration component of the water cycle. Condensation forms clouds, precipitation delivers water to the ground, and infiltration moves water into soil.

Question 41Natural Resources and Conservation

Which of the following is the most effective method for conserving water in irrigated agriculture?

  1. Irrigating at midday during the hottest hours
  2. Sprinkler and drip irrigation systems Correct answer.
  3. Leaving field channels unlined and open
  4. Flooding the entire field without measuring water use

Explanation

Drip and sprinkler systems deliver water directly to the root zone or as fine spray, greatly reducing losses from evaporation and deep percolation. Flood irrigation and unlined channels waste large volumes through runoff and seepage.

Question 42Natural Resources and Conservation

Which of the following is a major cause of soil salinity in irrigated agricultural land?

  1. Excessive irrigation without adequate drainage Correct answer.
  2. Planting leguminous crops in rotation
  3. Regular addition of organic compost
  4. Mulching the soil surface with crop residues

Explanation

Over-irrigation raises the water table, and when the water table is close to the surface, dissolved salts rise and accumulate as the water evaporates. Without drainage, salts build up in the root zone and reduce yields.

Question 43Natural Resources and Conservation

An environmental education programme wants to reduce pressure on a local forest. Which combination of measures best reflects the principle of sustainable resource management?

  1. Banning all community access and ignoring local livelihoods
  2. Meeting present needs while ensuring resources remain for future generations Correct answer.
  3. Exporting all forest produce without local processing
  4. Maximising extraction now to boost short-term income

Explanation

Sustainable management balances present-day use with the ability of future generations to meet their needs. It recognises that resources are finite and that equity across generations is part of sound resource planning.

Question 44Natural Resources and Conservation

Which of the following best illustrates the concept of 'carrying capacity' in resource management?

  1. The total number of species found in a forest
  2. The maximum population size an ecosystem can support without degradation Correct answer.
  3. The amount of rainfall received in a catchment
  4. The rate at which a river carries sediment downstream

Explanation

Carrying capacity is the maximum population that an area's resources can sustain indefinitely without degrading the resource base. Once population exceeds this level, overuse of soil, water and forests leads to environmental decline.

Question 45Natural Resources and Conservation

Which of the following describes the environmental benefit of recycling metals such as aluminium?

  1. It reduces the need to mine fresh ore and saves energy Correct answer.
  2. It increases the energy needed to produce new metal
  3. It permanently eliminates all mining activity
  4. It converts metal into a renewable resource

Explanation

Recycling aluminium requires far less energy than refining it from bauxite ore and reduces the demand for new mining. It conserves a finite mineral resource but does not make the metal renewable or eliminate mining entirely.

Question 46Natural Resources and Conservation

Which of the following is an example of a potential resource that has not yet been fully developed in Odisha?

  1. Timber already harvested from a managed plantation
  2. Solar energy potential over the state's arid western districts Correct answer.
  3. Coal already extracted from an operating mine
  4. Water already stored in a functioning reservoir

Explanation

A potential resource exists in the environment but is not yet being used to its full extent. Large stretches of land with high solar insolation represent such potential that can be developed with suitable technology.

Question 47Natural Resources and Conservation

Over-extraction of groundwater in a coastal region of Odisha can lead to which problem?

  1. Increased rainfall in the region
  2. Rapid recharge of the aquifer
  3. Saline seawater intrusion into the aquifer Correct answer.
  4. Rising groundwater levels

Explanation

When freshwater is pumped out faster than it is replenished, the water table falls and the hydraulic gradient reverses, allowing saline seawater to move inland into the aquifer. This makes the groundwater unsuitable for drinking and irrigation.

Question 48Natural Resources and Conservation

Which of the following is the main reason why fossil fuels are described as non-renewable?

  1. They are used only for cooking
  2. They release oxygen when burnt
  3. Their formation takes millions of years Correct answer.
  4. They are found only in coastal areas

Explanation

Fossil fuels form from buried organic matter over millions of years under heat and pressure. Human consumption occurs within decades, so the resource cannot be regenerated within a meaningful timeframe.

Question 49Natural Resources and Conservation

A community pond is being managed so that fish are harvested only after they reach maturity. This practice is an example of:

  1. Deforestation of a watershed
  2. Sustainable harvesting of a renewable resource Correct answer.
  3. Eutrophication of a water body
  4. Mining of a non-renewable resource

Explanation

Harvesting fish only after maturity allows the population to reproduce and replenish itself, which is the basis of sustainable use of a renewable biological resource. Removing immature fish would reduce future stocks.

Question 50Natural Resources and Conservation

Which of the following is the most direct consequence of soil erosion on agricultural productivity?

  1. Increase in soil organic matter
  2. Improvement in water-holding capacity
  3. Increase in soil depth
  4. Loss of nutrient-rich topsoil and decline in crop yield Correct answer.

Explanation

The topsoil layer is richest in organic matter and nutrients. When erosion removes it, the remaining subsoil is less fertile, so crop yields decline and more fertiliser is needed to compensate.