WBCS Mains Environment Ecology & Ecosystems Questions 2023

Q. The following ecosystem develops in flowing water:

(A) Lentic
(B) Lotic
(C) Benthic
(D) Pelagic

Correct Answer: (B) Lotic.

Q. Nor’wester in Assam is known as by which of the following name?

(A) Andhi
(B) Mango Shower
(C) Bordoisila
(D) Blossom

Correct Answer: (C) Bordoisila.

Q. Lichen is extremely sensitive to

(A) SO2
(B) CO2
(C) CO
(D) N2

Correct Answer: (A) SO2.

Q. The 10% law was provided by

(A) Odum
(B) Lindemann
(C) Tausley
(D) Darwin

Correct Answer: (B) Lindemann.

Q. The shape of the Diminishing Age Pyramid is

(A) Triangular
(B) Bell-shaped
(C) Urn-shaped
(D) None of these

Correct Answer: (C) Urn-shaped.

Q. Ecology was coined by

(A) Haeckel
(B) Odum
(C) Tausley
(D) Darwin

Correct Answer: (A) Haeckel.

Q. The following organism helps in denitrification:

(A) Fungi
(B) Bacteria
(C) Algae
(D) Protozoa

Correct Answer: (B) Bacteria.

Q. Water purity is denoted by the absence of

(A) CO2
(B) CO
(C) Coliform
(D) Entero bacter

Correct Answer: (C) Coliform.

Q. The nitrogen fixation in a paddy field is brought about by

(A) Bacteria
(B) Fern
(C) Cyano bacteria
(D) Algae

Correct Answer: (C) Cyano bacteria.

WBCS Mains Environment Ecology & Ecosystems Questions 2022

Q. Study of inter-relationships between organisms and their environment is

(A) ecology
(B) ecosystem
(C) phytogeography
(D) ethology

Correct Answer: (A) ecology.

Q. Which one of the following type of pollution is cultural eutrophication?

(A) Noise pollution
(B) Thermal pollution
(C) Soil pollution
(D) Water pollution

Correct Answer: (D) Water pollution.

Q. For individuals living in areas where no freshwater is available, which one of the following would produce water that could be used for drinking?

(A) Desalination
(B) Groundwater mining
(C) Sublimation
(D) Transpiration

Correct Answer: (A) Desalination.

Q. Which one of the following processes would remove nitrates from contaminated water by converting it into nitrogen gas?

(A) Nitrification
(B) Nitrogen fixation
(C) Denitrification
(D) Assimilation

Correct Answer: (C) Denitrification.

Q. Which one of the following is more indicative of conventional agriculture, and not sustainable agriculture?

(A) Biological control
(B) Intercropping
(C) Minimal tillage
(D) Integrated pest management

Correct Answer: (B) Intercropping.

Q. The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs

(A) the water vapour of the air and retains its heat.
(B) the ultraviolet part of the solar radiation.
(C) all the solar radiations.
(D) the infrared part of the solar radiation.

Correct Answer: (D) the infrared part of the solar radiation.

Q. What practice allows farmers to improve soil fertility, diversify their crops, and reduce pesticide costs by naturally breaking the cycle of weeds, insects, and diseases?

(A) Monoculture
(B) Biological control
(C) Crop sharing
(D) Crop rotation

Correct Answer: (D) Crop rotation.

Q. Food chain in which microorganisms breakdown the food formed by primary producers is

(A) parasitic food chain
(B) detritus food chain
(C) consumer food chain
(D) predator food chain

Correct Answer: (B) detritus food chain.

Q. What is the best pH of the soil for cultivation of plants?

(A) 3.4 – 5.4
(B) 6.5 – 7.5
(C) 4.5 – 8.5
(D) 5.5 – 6.5

Correct Answer: (B) 6.5 – 7.5.

Q. Huge solid waste liberated from Iron and Steel industry is

(A) Red mud
(B) Fly ash
(C) Bottom ash
(D) Granulated slag

Correct Answer: (D) Granulated slag.

Q. D.D.T. is

(A) not a pollutant
(B) an antibiotic
(C) a non-degradable pollutant
(D) a biodegradable pollutant

Correct Answer: (C) a non-degradable pollutant.

WBCS Mains Environment Ecology & Ecosystems Questions 2021

Q. Profuse growth of aquatic vegetation that often changes the colour of water body is known as

(A) Algal bloom
(B) Eutrophication
(C) Fermentation
(D) Both (A) and (B)

Correct Answer: (A) Algal bloom.

Q. El-Nino effect refers to periodic extension of warm equatorial current along which coast?

(A) Peru
(B) African
(C) East Coast of India
(D) Chilli Coast

Correct Answer: (A) Peru.

Q. Salinization is

(A) accumulation of salts in water
(B) accumulation of salts in soil
(C) accumulation of salts in body
(D) accumulation of salts in animals

Correct Answer: (B) accumulation of salts in soil.

Q. The fertility of soil is reduced by

(A) Ammonifying bacteria
(B) Denitrifying bacteria
(C) Nitrifying bacteria
(D) Nitrogen fixing bacteria

Correct Answer: (B) Denitrifying bacteria.

Q. The pyramid of number is inverted in the case of

(A) Parasitic food chain
(B) Forest ecosystem
(C) Grassland ecosystem
(D) Lake ecosystem

Correct Answer: (A) Parasitic food chain.

Q. ‘Entrophic’ water body is a

(A) highly productive water body rich in nutrient.
(B) water body poor in nutrient.
(C) fresh water body.
(D) stagnant water body.

Correct Answer: (A) highly productive water body rich in nutrient.

Q. Which of the following constitutes the largest ecosystem of the world?

(A) Ocean
(B) River
(C) Forest
(D) Grassland

Correct Answer: (A) Ocean.

WBCS Mains Environment Ecology & Ecosystems Questions 2020

Q. Which secondary pollutant is produced by UV rays of sun lights?

(A) SO2
(B) CO
(C) Fluorides
(D) O3

Correct Answer: (D) O3.

Q. Photochemical smog is related to pollution

(A) air
(B) water
(C) soil
(D) nostoc

Correct Answer: (A) air.

Q. Biome have

(A) plant communities
(B) animal communities
(C) trees only
(D) Both (A) and (B)

Correct Answer: (D) Both (A) and (B).

Q. Pollutants in soil can be broken by microorganisms. The process is called

(A) Probiotics
(B) Bioremediation
(C) Bio-augmentation
(D) None of the above

Correct Answer: (B) Bioremediation.

Q. Savannahs are

(A) Tropical rain forests
(B) Desert scrubs
(C) Grassland with scattered trees
(D) Dense forests with closed canopy

Correct Answer: (C) Grassland with scattered trees.

Q. Most abundant pollutant in the atmosphere among hydrocarbon is

(A) methane
(B) propane
(C) butane
(D) bezypyrene

Correct Answer: (A) methane.

Q. Mango necrosis (Black Tip) is due to

(A) SO2
(B) HCl
(C) PAH
(D) PAN

Correct Answer: (B) HCl.

Q. Overgrazing causes

(A) Negative pollution
(B) Positive pollution
(C) Soil erosion
(D) Reduction in crop yield

Correct Answer: (C) Soil erosion.

Q. Air pollutant causing leaf curling is

(A) SO2
(B) O3
(C) H2S
(D) CO

Correct Answer: (A) SO2.

Q. BOD stands for

(A) Biochemical Oxygen Demand
(B) Biotic Oxygen Dropping
(C) Biochemical Oxygen Dressing
(D) None of the above

Correct Answer: (A) Biochemical Oxygen Demand.

Q. Peeling of Ozone umbrella is due to

(A) CFCs
(B) PAN
(C) CO2
(D) Coal burning

Correct Answer: (A) CFCs.

WBCS Mains Environment Ecology & Ecosystems Questions 2019

Q. Habitats resulting from lava flow is an example of

(A) primary succession
(B) secondary succession
(C) autogenic succession
(D) allogenic succession

Correct Answer: (A) primary succession.

Q. The following is a sedentary cycle:

(A) P cycle
(B) N cycle
(C) C cycle
(D) O2 cycle

Correct Answer: (A) P cycle.

Q. The following gas may be involved in stone cancer:

(A) N2
(B) SO2
(C) CO2
(D) H2S

Correct Answer: (B) SO2.

Q. An ecosystem consists of

(A) population.
(B) a biotic community.
(C) a population and its non-living elements.
(D) a biotic community and its non-living elements.

Correct Answer: (D) a biotic community and its non-living elements.

Q. Biotic environment includes

(A) Consumers
(B) Decomposers
(C) Producers
(D) All of the above

Correct Answer: (D) All of the above.

Q. The permanent decrease in population number occurs due to

(A) Migration
(B) Natality
(C) Emigration
(D) Mortality

Correct Answer: (C) Emigration.

Q. X-ray films are a source of which of the following gas?

(A) SO2
(B) CO2
(C) NO2
(D) SO3

Correct Answer: (C) NO2.

Q. Which is the most abundant hydrocarbon in the atmosphere?

(A) Methane
(B) Carbonyl sulphide
(C) Ethane
(D) None of the above

Correct Answer: (A) Methane.

WBCS Mains Environment Ecology & Ecosystems Questions 2018

Q. In which ecosystem, grassland is included?

(A) Marine
(B) Freshwater
(C) Terrestrial
(D) Artificial

Correct Answer: (C) Terrestrial.

Q. The largest reservoir of nitrogen gas in environment is

(A) Air
(B) Earth’s Crust
(C) Ocean
(D) Plants and animals

Correct Answer: (A) Air.

Q. Soil is rarely contaminated due to

(A) Acid rain
(B) Chemical fertilizers
(C) Pesticides
(D) Mineralisation

Correct Answer: (D) Mineralisation.

Q. Which part of atmosphere is richest in O3 gas?

(A) Stratosphere
(B) Ionosphere
(C) Exosphere
(D) Magnetosphere

Correct Answer: (A) Stratosphere.

Q. Hydrosphere does not cover

(A) Oceans
(B) Rivers
(C) Glaciers
(D) Rocks

Correct Answer: (D) Rocks.

Q. Which one of the following is not included within the atmosphere?

(A) Troposphere
(B) Stratosphere
(C) Lithosphere
(D) Ozonosphere

Correct Answer: (C) Lithosphere.

Q. The scavengers of the earth is

(A) Bacteria
(B) Viruses
(C) Algae
(D) Fungi

Correct Answer: (D) Fungi.

WBCS Mains Environment Ecology & Ecosystems Questions 2017

Q. Which state was declared on January 18, 2016 as the first organic farming state of India?

(A) Kerala
(B) Goa
(C) Sikkim
(D) Telangana

Correct Answer: (C) Sikkim.

Q. Humidity is the result of

(A) Evaporation
(B) Transpiration
(C) Presence of heat
(D) Moisture content in the air

Correct Answer: (D) Moisture content in the air.

Q. In ecosystem, which one shows one way passage?

(A) Free energy
(B) Nitrogen
(C) Carbon
(D) Potassium

Correct Answer: (A) Free energy.

Q. Main source of water and soil pollution is

(A) Agro industry
(B) Thermal power plant
(C) Industrial effluents
(D) All of the above

Correct Answer: (D) All of the above.

Q. Which one of the following clay has the highest cation exchange capacity (CEC)?

(A) Bentonite
(B) Halloysite
(C) Ball clay
(D) China clay

Correct Answer: (A) Bentonite.

WBCS Mains Environment Ecology & Ecosystems Questions 2015

Q. Flowing water ecosystem is also called

(A) Pelagic
(B) Estuarine
(C) Lotic
(D) Lentic

Correct Answer: (C) Lotic.

Q. Acid rain can be caused by the pollution of environment by

(A) CO2 and N2
(B) CO and CO2
(C) O3 and CO3
(D) N2O and SO2

Correct Answer: (D) N2O and SO2.

Q. Cigarette smoking is harmful for health due to the emission of

(A) CO2
(B) CO
(C) KMnO4
(D) SO2

Correct Answer: (B) CO.

Q. Land fill gas is other name of

(A) CO2
(B) CO
(C) H2S
(D) CH4

Correct Answer: (D) CH4.

WBCS Mains Environment Ecology & Ecosystems Questions 2014

Q. An estuary is a

(A) Body of water
(B) coastal body of water
(C) semiclosed coastal body of water
(D) water body of lake

Correct Answer: (C) semiclosed coastal body of water.

Q. Natural source of O2 in environment is

(A) Respiration
(B) Transpiration
(C) Photosynthesis
(D) Combustion

Correct Answer: (C) Photosynthesis.

Q. Contamination of which metal with soil makes it hard for trees to take up water?

(A) Aluminium
(B) Magnesium
(C) Copper
(D) Zinc

Correct Answer: (A) Aluminium.

Q. Which ocean is involved with the emergence of the La Nina climate pattern?

(A) The global ocean
(B) The Pacific ocean
(C) The Atlantic ocean
(D) The Indian ocean

Correct Answer: (B) The Pacific ocean.