UPSC Prelims Environment & Ecology PYQs with Explanations

With reference to the food chains in ecosystems, which of the following kinds of an organism is/are known as decomposer organism/organisms?

1. Virus
2. Fungi
3. Bacteria

Select the correct answer using the codes given below.

Which of the following adds/add nitrogen to the soil?

1. Excretion of urea by animals
2. Burning of coal by man
3. Death of vegetation

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Which of the following are detritivores?

1. Earthworms
2. Jellyfish
3. Millipedes
4. Seahorses
5. Woodlice

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In the grasslands, trees do not replace the grasses as a part of an ecological succession because of

Lichens, which are capable of initiating ecological succession even on a bare rock, are actually a symbiotic association of

With reference to food chains in ecosystems, consider the following statements :

1. A food chain illustrates the order in which a chain of organisms feeds upon each other.
2. Food chains are found within the populations of a species.
3. A food chain illustrates the numbers of each organism which are eaten by others.

Which of the statements given above is/are correct?

In case of which one of the following biogeochemical cycles, the weathering of rocks is the main source of release of nutrient to enter the cycle?

Consider the following :

1. Photosynthesis.
2. Respiration.
3. The decay of organic matter.
4. Volcanic action.

Which of the above add carbon dioxide to the carbon cycle on Earth?

Which one of the following shows a unique relationship with an insect that has coevolved with it and that is the only insect that can pollinate this tree?

Which of the following are in Agasthyamala Biosphere Reserve?

Which of the following National Parks is unique in being a swamp with floating vegetation that supports rich biodiversity?

If you walk through the countryside, you are likely to see some birds stalking alongside the cattle to seize the insects, disturbed by their movement through grasses, Which of the following is/are such bird/birds?

1. Painted Stork
2. Common Myna
3. Black-necked Crane

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With reference to ‘Red Sanders’, sometimes seen in the news, consider the following statements:

1. It is a tree species found in a part of South India.
2. It is one of the most important trees in the tropical rainforest areas of South India.

Which of the statements given above is/are correct?

With reference to India’s biodiversity, Ceylon frogmouth, Coppersmith barbet, Gray-chinned minivet and White-throated redstart are

Consider the following statements:

1. Some species of turtles are herbivores.
2. Some species of fish are herbivores.
3. Some species of marine mammals are herbivores.
4. Some species of snakes are viviparous.

Which of the statements given above are correct?

What is/are unique about ‘Kharai camel’ a breed found in India?

1. It is capable of swimming up to three kilometres in seawater.
2. It survives by grazing on mangroves.
3. It lives in the wild and cannot be domesticated.

Recently, for the first time in our country, which of the following State has declared a particular butterfly as ‘State Butterfly’?

Why is a plant called Prosopis juliflora often mentioned in the news?

Which one of the following National Parks lies completely in the temperate alpine zone?

Recently, there was a growing awareness in our country about the importance of Himalayan nettle (Girardinia diversifolia) because it is found to be a sustainable source of

With reference to the Neem tree, consider the following statements:

1. Neem oil can be used as a pesticide to control the proliferation of some species of insects and mites.
2. Neem seeds are used in the manufacture of biofuels and hospital detergents.
3. Neem oil has applications in the pharmaceutical industry.

Which of the statements given above is/are correct?

Consider the following;

1. Carbon monoxide
2. Nitrogen oxide
3. Ozone
4. Sulphur dioxide

Excess of which of the above in the environment is/are the cause(s) of acid rain?

Consider the following:

1. Aerosols
2. Foam agents
3. Fire retardants
4. Lubricants

In the making of how many of the above are hydrofluorocarbons used?

According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?

Artificial way of causing rainfall to reduce air pollution makes use of

With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements :

1. PFAS are found to be widespread in drinking water, food and food packaging materials.
2. PFAS are not easily degraded in the environment.
3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies.

Which of the statements given above are correct?

Consider the following:

I. Cigarette butts II. Eyeglass lenses III. Car tyres

How many of them contain plastic?

Consider the following statements :

Statement-I: Many chewing gums found in the market are considered a source of environmental pollution. Statement-II: Many chewing gums contain plastic as gum base.

Which one of the following is correct in respect of the above statements?

Consider the following statements:

Statement I: Circular economy reduces the emissions of greenhouse gases.

Statement II: Circular economy reduces the use of raw materials as inputs.

Statement III: Circular economy reduces wastage in the production process.

Which one of the following is correct in respect of the above statements?

Consider the following statements:

Statement I: Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions.

Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement.

Statement III: Limestone is converted into lime during clinker production for cement manufacturing.

Which one of the following is correct in respect of the above statements?

Consider the following statements regarding mercury pollution:

1. Gold mining activity is a source of mercury pollution in the world.
2. Coal-based thermal power plants cause mercury pollution.
3. There is no known safe level of exposure to mercury.

How many of the above statements are correct?

"Momentum for Change: Climate Neutral Now" is an initiative launched by

Which one of the following statements best describes the term ‘Social Cost of Carbon’?

The ‘Common Carbon Metric’, supported by UNEP, has been developed for

What is blue carbon?

Consider the following statements:

1. Agricultural soils release nitrogen oxides into the environment.
2. Cattle release ammonia into the environment.
3. Poultry industry releases reactive nitrogen compounds into environment.

Which of the statements given above is/are correct?

With reference to the ‘New York Declaration on Forests’. Which of the following statements are correct?

1. It was first endorsed at the United Nations Climate Summit in 2014.
2. It endorses a global timeline to end the loss of forests.
3. It is a legally binding international declaration.
4. It is endorsed by governments, big companies and indigenous communities.
5. India was one of the signatories at its inception.

Select the Correct answer using the code given below.

The term "sixth mass extinction/sixth extinction" is often mentioned in the news in the context of the discussion of

In the context of India’s preparation for Climate-smart Agriculture, consider the following statements:

1. The ‘Climate-Smart Village’ approach in India is a part of a project led by the Climate Change, Agriculture and Food Security (CCAFS), an international research programme.
2. The project of CCAFS is carried out under Consultative Group on International Agricultural Research (CGIAR) headquartered in France.
3. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in India is one of the CGIAR’s research centres.

Which of the statements given above are correct?

With reference to the 'Global Alliance for Climate-Smart Agriculture (GACSA)', which of the following statements is/are correct.

1. GACSA is an outcome of the Climate Summit held in Paris in 2015.
2. Membership of GACSA does not create any binding obligations.
3. India was instrumental in the creation of GACSA.

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Consider the following statements:

1. CoaI sector was nationalized by the Government of India under Indira Gandhi.
2. Now, coal blocks are allocated on a lottery basis.
3. Till recently, India imported coal to meet the shortage of domestic supply, but now India is self- sufficient in coal production.

Which of the statements given above is/arc correct?

If you want to see gharials in their natural habitat, which one of the following is the best place to visit?

Recently there was a proposal to translocate some of the lions from their natural habitat in Gujarat to which one of the following sites?

Vultures which used to be very common in the Indian countryside some years ago are rarely seen nowadays. This is attributed to

Other than poaching, what are the possible reasons for the decline in the population of Ganges River Dolphins?

1. Construction of dams and barrages on rivers
2. Increase in the population of crocodiles in rivers
3. Getting trapped in fishing nets accidentally
4. Use of synthetic fertilizers and other agricultural chemicals in crop-fields in the vicinity of rivers

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Recently, "oil zapper" was in the news. What is it?

With reference to Indian elephants, consider the following statements:

1. The leader of an elephant group is a female.
2. The maximum gestation period can be 22 months.
3. An elephant can normally go on calving till the age of 40 years only.
4. Among the States in India, the highest elephant population is in Kerala.

Which of the statements given above is/are correct?

Which of the following Protected Areas are located in Cauvery basin?

1. Nagarhole National Park
2. Papikonda National Park
3. Sathyamangalam Tiger Reserve
4. Wayanad Wildlife Sanctuary

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In which one of the following States is Pakhui Wildlife Sanctuary located?

With reference to India’s Desert National Park, which of the following statements are correct?

1. It is spread over two districts.
2. There is no human habitation inside the Park.
3. It is one of the natural habitats of Great Indian Bustard.

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In which one among the following categories of protected areas in India are local people not allowed to collect and use the biomass?