Class-12 Biology Ch-16 Environmental Issues MCQs Exam 2027

Unit: Ecology and Environment

Chapter 1: Organisms and Populations

1. Which of the following is an example of desert adaptation? [2021A]

   (A) Opuntia

   (B) Trapa

   (C) Lotus

   (D) Cuscuta

2. Water holding capacity is a property of which of the following? [2019A]

   (A) Soil

   (B) Plants

   (C) Water

   (D) Animals

3. How are the stomata in desert plants? [2026A]

   (A) Sunken

   (B) Very large

   (C) Absent

   (D) On the upper surface of the leaf

4. Which method is used to measure population density? [2026A]

   (A) Biomass

   (B) Number

   (C) Percent cover

   (D) All of these

5. What is the interaction between two different species called? [2026A]

   (A) Interspecific interaction

   (B) Intraspecific interaction

   (C) Competition

   (D) Predation

6. Lichen is an example of which of the following? [2026A]

   (A) Mutualism

   (B) Commensalism

   (C) Parasitism

   (D) Predation

7. Which of the following is the pollinating agent of Ophrys? [2026A]

   (A) Wasp

   (B) Hummingbird

   (C) A species of bee

   (D) Bat

8. Which of the following processes decreases population density? [2026A]

   (A) Immigration

   (B) Death

   (C) Emigration

   (D) Both (B) and (C)

9. Which of the following was used to control the cactus introduced in Australia? [2026A]

   (A) Moth

   (B) Calotropis

   (C) Phytophagous insects

   (D) Virus

10. What is a group of individuals of the same species living in an area called? [2026A]

    (A) Community

    (B) Population

    (C) Ecosystem

    (D) Biome

Chapter 2: Ecosystem

11. Who first proposed the ecological pyramid? [2022A]

    (A) Charles Elton

    (B) R. Mishra

    (C) E.P. Odum

    (D) Tansley

12. What percentage of energy is transferred from one trophic level to another? [2021A]

    (A) 5%

    (B) 10%

    (C) 15%

    (D) 20%

13. Secondary productivity is related to which of the following? [2021A]

    (A) Producer

    (B) Herbivore

    (C) Carnivore

    (D) None of these

14. Decomposers are— [2024A]

    (A) Autotrophs

    (B) Heterotrophs

    (C) Fungi and Bacteria

    (D) Animals

15. Who first used the term ‘Ecosystem’? [2022A]

    (A) Odum

    (B) Tansley

    (C) Warming

    (D) Gardner

16. What is the ‘Pyramid of Energy’ like in an aquatic ecosystem? [2023A]

    (A) Always upright

    (B) Always inverted

    (C) Bell-shaped

    (D) None of these

17. Which of the following pyramids is never inverted? [2024A]

    (A) Pyramid of Number

    (B) Pyramid of Biomass

    (C) Pyramid of Energy

    (D) None of these

18. Who has the highest number in a Food Chain? [2022A]

    (A) Producer

    (B) Primary Consumer

    (C) Secondary Consumer

    (D) Decomposer

19. The main source of energy in an ecosystem is— [2021A]

    (A) Green plants

    (B) Sunlight

    (C) Air

    (D) All of these

20. Which of the following is not a primary consumer of an ecosystem? [2026A]

    (A) Zooplankton

    (B) Cow

    (C) Grasshopper

    (D) Wolf

21. What percentage of PAR is captured by plants? [2026A]

    (A) 50%

    (B) 2-10%

    (C) 10%

    (D) 20%

22. What is the raw material for decomposition called? [2026A]

    (A) Humus

    (B) Inorganic substance

    (C) Detritus

    (D) Organic substance

23. What are secondary consumers called? [2026A]

    (A) Herbivores

    (B) Primary carnivores

    (C) Secondary carnivores

    (D) Consumers

24. Organisms that obtain energy from dead organic matter are called— [2026A]

    (A) Saprotrophs

    (B) Heterotrophs

    (C) Detritivores

    (D) Parasite

25. How is the flow of energy in a food chain? [2026A]

    (A) Unidirectional

    (B) Bidirectional

    (C) Multidirectional

    (D) Cyclic

26. In ecosystem terminology, ‘green plants’ are called— [2026A]

    (A) Consumers

    (B) Producers

    (C) Decomposers

    (D) None of these

27. Which of the following food chains is correct? [2026A]

    (A) Grass, Wheat, and Mango

    (B) Grass, Goat, and Lion

    (C) Goat, Cow, and Elephant

    (D) Grass, Fish, and Goat

28. Who gave the ’10 percent law’ of energy in an ecosystem? [2026A]

    (A) Lindeman

    (B) Tansley

    (C) Odum

    (D) Darwin

29. Which of the following has the highest Biomass in an aquatic ecosystem? [2026A]

    (A) Fish

    (B) Aquatic plants

    (C) Phytoplankton

    (D) None of these

30. Energy flow in a Food Web is— [2026A]

    (A) Unidirectional

    (B) Bidirectional

    (C) Multidirectional

    (D) Cyclic

31. What are herbivorous animals called in an ecosystem? [2026A]

    (A) Primary Producers

    (B) Primary Consumers

    (C) Secondary Consumers

    (D) Tertiary Consumers

32. What is the final stage of Ecological Succession called? [2026A]

    (A) Seral stage

    (B) Pioneer stage

    (C) Climax Community

    (D) Transitional stage

33. Where is an inverted pyramid of Biomass found? [2026A]

    (A) In a forest

    (B) In a grassland

    (C) In the sea

    (D) In a desert

34. Why is the earthworm called the ‘friend of farmers’? [2026A]

    (A) It makes the soil porous/loose

    (B) It kills insects

    (C) It destroys weeds

    (D) None of these

35. What is the role of ‘Decomposers’ in a food chain? [2026A]

    (A) Energy production

    (B) Recycling of nutrients

    (C) Absorption of solar energy

    (D) None of these

Chapter 3: Biodiversity and Conservation

36. What is the number of biodiversity ‘Hot Spots’ in the world? [2018A]

    (A) 25

    (B) 34

    (C) 9

    (D) 15

37. In which state is the ‘Rhino Sanctuary’ located? [2020A]

    (A) Assam

    (B) West Bengal

    (C) Uttar Pradesh

    (D) Bihar

38. Gir Sanctuary is famous for— [2020A]

    (A) Birds

    (B) Lions

    (C) Elephants

    (D) None of these

39. Where is Kanha National Park located? [2019A]

    (A) Uttar Pradesh

    (B) Madhya Pradesh

    (C) Gujarat

    (D) Rajasthan

40. Chipko Movement was started for the protection of— [2020A]

    (A) Forest

    (B) Grassland

    (C) Wetland

    (D) Desert

41. An example of Ex-situ conservation is— [2021A]

    (A) Sacred Groves

    (B) National Park

    (C) Seed Bank

    (D) Wildlife Sanctuary

42. Red Data Book includes— [2021A]

    (A) List of extinct plants

    (B) List of rare plants

    (C) List of endangered animals

    (D) All of these

43. Where is Sundarban National Park located? [2020A]

    (A) Bihar

    (B) West Bengal

    (C) Assam

    (D) Madhya Pradesh

44. Kanha National Park is famous for— [2023A]

    (A) Birds

    (B) Tigers

    (C) Rhinos

    (D) Crocodiles

45. Which is the exact example of Ex-situ conservation? [2023A]

    (A) Zoological Park

    (B) Wildlife Sanctuary

    (C) Biosphere Reserve

    (D) National Park

46. Kaziranga National Park is famous for— [2021A]

    (A) Lion

    (B) Tiger

    (C) One-horned Rhino

    (D) Deer

47. Who gave the term ‘Biodiversity’? [2021A]

    (A) Edward Wilson

    (B) Raymond Dasmann

    (C) Walter G. Rosen

    (D) A.G. Tansley

48. What was the reason for the extinction of Cichlid fish in Lake Victoria? [2024A]

    (A) Co-extinction

    (B) Invasion of alien species

    (C) Over-exploitation

    (D) Habitat loss

49. When was ‘Project Tiger’ started in India? [2018A]

    (A) 1973

    (B) 1983

    (C) 1993

    (D) 2003

50. Dodo is— [2019A]

    (A) Extinct species

    (B) Endangered species

    (C) Threatened species

    (D) None of these

51. Which is called the “Lungs of the earth”? [2026A]

    (A) Forest

    (B) Temperate region

    (C) Amazon rainforest

    (D) Tropical Savannah

52. Which species became extinct due to over-exploitation? [2026A]

    (A) Passenger pigeon

    (B) Giant Panda

    (C) Nile Perch

    (D) Cichlid fish

53. Economic benefits from nature is what type of argument for biodiversity? [2026A]

    (A) Narrowly utilitarian

    (B) Broadly utilitarian

    (C) Ethical

    (D) All of these

54. How many ‘Mega-biodiversity’ countries are in the world? [2026A]

    (A) 25

    (B) 34

    (C) 14

    (D) 17

55. Due to frequent glaciation, which region got less time for evolution? [2026A]

    (A) Temperate region

    (B) Tropical region

    (C) Polar region

    (D) All regions

56. In a National Park, protection is provided to— [2026A]

    (A) Only fauna

    (B) Only flora

    (C) Entire ecosystem

    (D) Only birds

57. What is the fundamental source of biodiversity? [2026A]

    (A) Mutation

    (B) Adaptation

    (C) Recombination

    (D) None of these

58. What is the National Aquatic Animal of India? [2026A]

    (A) Hippopotamus

    (B) River Dolphin (Gangetic Dolphin)

    (C) Blue Whale

    (D) Sea Turtle

59. Who publishes the Red Data Book? [2026A]

    (A) WWF

    (B) IUCN

    (C) WHO

    (D) UNESCO

60. When was the Wildlife Protection Act implemented? [2026A]

    (A) 1972

    (B) 1986

    (C) 1991

    (D) 2002

61. Which is the main animal of Sundarban? [2026A]

    (A) Bengal Tiger

    (B) Asian Elephant

    (C) One-horned Rhino

    (D) Wild Ass

62. Where was the Earth Summit 1992 held? [2026A]

    (A) New York

    (B) Rio de Janeiro

    (C) Johannesburg

    (D) New Delhi

63. What is the basis for declaring a Biodiversity ‘Hotspot’? [2026A]

    (A) Number of species

    (B) Endemism

    (C) Degree of threat

    (D) All of these

64. Where are Sacred Groves found? [2026A]

    (A) Khasi and Jaintia Hills of Meghalaya

    (B) Aravalli Hills of Rajasthan

    (C) Western Ghats of Karnataka

    (D) All of the above

65. What is the main cause of loss in biodiversity? [2026A]

    (A) Habitat loss

    (B) Pollution

    (C) Alien species invasion

    (D) All of these

Chapter 4: Environmental Issues

66. In which unit is the thickness of Ozone measured? [2018A]

    (A) Dobson unit

    (B) Arab unit

    (C) Pascal unit

    (D) None of these

67. Which of the following is an effect of deforestation? [2022A]

    (A) Increase in $CO_2$ concentration

    (B) Desertification

    (C) Global warming

    (D) All of these

68. What is always present in photochemical smog? [2023A]

    (A) $CO$

    (B) $O_3$

    (C) $SO_2$

    (D) $CH_4$

69. On which date is World Environment Day celebrated? [2022A]

    (A) June 5

    (B) December 20

    (C) March 15

    (D) July 7

70. The pH of acid rain is below— [2022A]

    (A) 5.6

    (B) 6

    (C) 6.5

    (D) 7

71. Ozone hole is caused by—

    (A) Acetylene

    (B) Ethylene

    (C) Chlorofluorocarbon

    (D) Methane

72. Lichen is an indicator of— [2021A]

    (A) $CO_2$ pollution

    (B) $SO_2$ pollution

    (C) $CO$ pollution

    (D) Water pollution

73. What happens due to the presence of excessive nutrients in water? [2023A]

    (A) Eutrophication

    (B) Denitrification

    (C) Nitrification

    (D) None of these

74. When is Ozone Day celebrated? [2018A]

    (A) September 16

    (B) April 21

    (C) December 25

    (D) January 30

75. The result of the adverse effect of radioactive pollutants is— [2022A]

    (A) Tuberculosis

    (B) Polio

    (C) Hepatitis

    (D) Gene mutation

76. Indicator of $SO_2$ pollution is— [2021A]

    (A) Algae

    (B) Lichen

    (C) Fungi

    (D) None of these

77. Which is not a cause of global warming? [2024A]

    (A) Use of fossil fuels

    (B) Deforestation

    (C) Population explosion

    (D) Improvement in energy use efficiency

78. Biogas contains— [2021A]

    (A) $CO_2$

    (B) $H_2S$

    (C) $CH_4$

    (D) All of these

79. In which layer is the Ozone level found?

    (A) Troposphere

    (B) Stratosphere

    (C) Mesosphere

    (D) Exosphere

80. What is the main source of harmful radiation in homes?

    (A) Tubelight

    (B) Color TV

    (C) Stove

    (D) Heater

81. What is the unit for measuring noise pollution? [2023A]

    (A) Hertz

    (B) Nanometer

    (C) Decibel

    (D) Light year

82. Ozone layer protects the earth from which harmful radiation? [2020A]

    (A) Gamma rays

    (B) Ultraviolet (UV) radiation

    (C) X-rays

    (D) Infrared rays

83. The main factor of ‘Greenhouse effect’ is—

    (A) CFCs

    (B) $CO_2$

    (C) $CO$

    (D) $CH_4$

84. What is the main cause of snow blindness in humans? [2018A]

    (A) Absorption of UV-B radiation

    (B) Absorption of infra radiation

    (C) Absorption of cosmic radiation

    (D) Snow erosion of cornea

85. Who among the following is related to ‘Polyblend’? [2020A]

    (A) Ahmed Khan

    (B) Ramesh Chandra Dagar

    (C) Ramdeo Misra

    (D) Swaminathan

86. What is the current atmospheric $CO_2$ concentration?

    (A) 100 ppm

    (B) 240 ppm

    (C) 380 ppm

    (D) 520 ppm

87. What is the main cause of ozone layer depletion? [2019A]

    (A) CO

    (B) $CO_2$

    (C) CFCs

    (D) $CH_4$

88. Sanitary landfills were adopted as a substitute for— [2023A]

    (A) Open burning dumps

    (B) Eutrophic

    (C) Bio-magnification

    (D) Sewage

89. Which of the following is not a ‘Greenhouse gas’? [2022A]

    (A) Methane

    (B) Nitrogen

    (C) $CO_2$

    (D) Chlorofluorocarbon

90. Which of the following shows Biomagnification? [2022A]

    (A) DDT

    (B) Mercury

    (C) Both (A) and (B)

    (D) $SO_2$

91. ‘Green Muffler’ is related to which pollution?

    (A) Soil

    (B) Air

    (C) Noise

    (D) Water

92. Global warming can be controlled by—

    (A) Reducing deforestation

    (B) Reducing fossil fuel use

    (C) Reducing population growth rate

    (D) All of these

93. Excess of E. coli in water indicates— [2020A]

    (A) Salinity of water

    (B) Industrial pollution

    (C) Sewage pollution

    (D) All of these

94. Factors of acid rain are—

    (A) $CO$ and $CO_2$

    (B) $NO_2$ and $SO_2$

    (C) $CO_2$ and $NO_2$

    (D) $N_2$ and $NO_3$

95. The major source of methane is—

    (A) Fruit plantation

    (B) Rice field (Paddy)

    (C) Wheat field

    (D) Horticulture

96. Humans can generally tolerate sound intensity of—

    (A) 20-30 Decibels

    (B) 80-90 Decibels

    (C) 120-130 Decibels

    (D) 140-150 Decibels

97. Greenhouse effect is due to— [2018A]

    (A) High $CO_2$ concentration

    (B) Presence of Infrared rays

    (C) Absorption by moisture and dust

    (D) Both (A) and (B)

98. Which is affected by $SO_2$ pollution?

    (A) Mitochondria

    (B) Chloroplast

    (C) Golgi body

    (D) ER

99. The world’s climate is in danger due to—

    (A) Increase in $CO_2$

    (B) Increase in $O_2$

    (C) Increase in Ozone

    (D) Increase in $N_2$

100. When was the Environment Protection Act passed?

     (A) 1986

     (B) 1981

     (C) 1974

     (D) 1968

101. What is the biggest factor of air pollution? [2018A]

     (A) Carbon dioxide

     (B) Smoke

     (C) Carbon monoxide

     (D) Sulfur dioxide

102. What is not found in photochemical smog? [2020A]

     (A) PAN

     (B) Sulfur dioxide

     (C) Sulfur trioxide

     (D) Carbon dioxide

103. Chipko Movement is related to— [2018A]

     (A) Planting trees

     (B) Saving trees from being cut

     (C) Tobacco prohibition

     (D) Water conservation

104. Cause of acidity of rain water is— [2026A]

     (A) $SO_2$ and $NO_2$

     (B) $CO$ and $CO_2$

     (C) Dust particles

     (D) Water vapor

105. Which acid is found in acid rain? [2026A]

     (A) $H_2SO_4$

     (B) $HNO_3$

     (C) Both (A) and (B)

     (D) $HCl$

106. Bhopal Gas Tragedy occurred due to the leakage of— [2026A]

     (A) Methyl Isocyanate

     (B) Carbon monoxide

     (C) Chlorine

     (D) Ammonia

107. What is the result of overgrazing? [2026A]

     (A) Soil Erosion

     (B) Increase in rain

     (C) Increase in soil fertility

     (D) None of these

108. What is the main cause of Eutrophication? [2026A]

     (A) Agricultural runoff

     (B) Thermal pollution

     (C) Noise pollution

     (D) Air pollution

109. Which of the following is a natural indicator of ‘Air Pollution’? [2026A]

     (A) Lichen

     (B) Algae

     (C) Fungi

     (D) Bryophyta

110. Kyoto Protocol is related to— [2026A]

     (A) Ozone layer protection

     (B) Greenhouse effect (Global Warming)

     (C) Water pollution

     (D) Wildlife protection

111. Increase in DDT concentration at the next level of a food chain is— [2026A]

     (A) Bio-accumulation

     (B) Bio-magnification

     (C) Eutrophication

     (D) Mineralization

112. What is the effect of increasing ‘CO2’ in the environment? [2026A]

     (A) Temperature decreases

     (B) Temperature increases

     (C) Rain stops

     (D) No effect

Other Important Topics: Genetics, Biotech & Health

113. What does the Operon model represent? [2019A]

     (A) Gene synthesis

     (B) Gene expression

     (C) Gene regulation

     (D) Gene function

114. How many characters did Mendel study? [2018A]

     (A) 5

     (B) 7

     (C) 14

     (D) 10

115. What is the number of chromosomes in Turner’s Syndrome? [2022A]

     (A) 44

     (B) 45

     (C) 46

     (D) 47

116. What is tested by PCR? [2022A]

     (A) HIV

     (B) Tuberculosis

     (C) Cholera

     (D) Cancer

117. Who discovered Double Fertilization? [2019A]

     (A) Leeuwenhoek

     (B) Strasburger

     (C) Nawaschin

     (D) None of these

118. Agarose is obtained from— [2020A]

     (A) Seaweed

     (B) Maize

     (C) Cycas

     (D) None of these

119. In Pasteurization, liquids are heated at— [2021A]

     (A) Only milk

     (B) Any liquid at $100^{\circ}C$

     (C) Any liquid at $70^{\circ}C$ to $80^{\circ}C$

     (D) None of these

120. Uterus is related to— [2020A]

     (A) Male reproductive system

     (B) Female reproductive system

     (C) Plant reproductive system

     (D) All of these

121. Copper-T (CuT) prevents— [2021A]

     (A) Fertilization

     (B) Ovulation

     (C) Ejaculation

     (D) None of these

122. Minamata disease is caused by poisoning of—

     (A) Methyl Mercury

     (B) Methyl Cyanide

     (C) Lead

     (D) Copper

123. What did Darwin see on Galapagos Islands? [2020A]

     (A) Finches

     (B) Turtle

     (C) Kangaroo

     (D) All of these

124. Which is an exception to Mendel’s laws?

     (A) Dominance

     (B) Purity of gametes

     (C) Linkage

     (D) Independent assortment

125. Pyrimidines of DNA contain—

     (A) Thymine and Cytosine

     (B) Adenine and Guanine

     (C) Cytosine and Uracil

     (D) Thymine and Uracil

126. AIDS is caused by—

     (A) Fungi

     (B) Virus (HIV)

     (C) Bacteria

     (D) Helminth

127. Typhoid is confirmed by which test?

     (A) ELISA

     (B) Widal Test

     (C) PCR

     (D) ESR

128. Who is the vector of Malaria?

     (A) Female Anopheles mosquito

     (B) Male Anopheles mosquito

     (C) Female Culex mosquito

     (D) None of these

129. Cancer is caused by—

     (A) Oncogenes

     (B) Bacteria

     (C) Fungi

     (D) None of these

130. When is World AIDS Day celebrated?

     (A) May 1

     (B) December 1

     (C) June 5

     (D) December 20

131. What is the ploidy of Endosperm?

     (A) n

     (B) 2n

     (C) 3n

     (D) 4n

132. Aril is edible in—

     (A) Custard apple

     (B) Litchi

     (C) Nutmeg

     (D) All of these

133. Who is the father of Genetics?

     (A) Darwin

     (B) Mendel

     (C) Lamarck

     (D) De Vries

134. What is the basis of DNA Fingerprinting?

     (A) DNA Polymorphism

     (B) Protein synthesis

     (C) RNA synthesis

     (D) None of these

135. Bt cotton resists—

     (A) Insects

     (B) Weeds

     (C) Salt

     (D) Drought

136. Golden Rice is rich in—

     (A) Vitamin A

     (B) Vitamin C

     (C) Vitamin B12

     (D) Vitamin D

137. What was the name of the first transgenic cow?

     (A) Dolly

     (B) Rosie

     (C) Molly

     (D) Beauty

138. Which enzyme cuts DNA?

     (A) Ligase

     (B) Restriction endonuclease

     (C) Polymerase

     (D) Helicase

139. Which enzyme joins DNA fragments?

     (A) Ligase

     (B) Endonuclease

     (C) Helicase

     (D) Protease

140. Biotechnology is used in—

     (A) Agriculture

     (B) Medicine

     (C) Industry

     (D) All of these

141. ELISA test is used to detect—

     (A) Cancer

     (B) AIDS

     (C) Typhoid

     (D) Malaria

142. Sweet potato is a modification of—

     (A) Root

     (B) Stem

     (C) Leaf

     (D) Fruit

143. Potato is a—

     (A) Root

     (B) Underground stem (Tuber)

     (C) Fruit

     (D) Seed

144. What is the male part of a flower called?

     (A) Gynoecium

     (B) Androecium

     (C) Corolla

     (D) Calyx

145. After fertilization, the ovary turns into—

     (A) Seed

     (B) Fruit

     (C) Flower

     (D) Embryo

146. Self-pollination is found in—

     (A) Bisexual flowers

     (B) Unisexual flowers

     (C) Both (A) and (B)

     (D) None of these

147. Which plant did Mendel choose for his experiments?

     (A) Rose

     (B) Garden Pea

     (C) Mustard

     (D) Hibiscus

148. Total number of chromosomes in humans is—

     (A) 44

     (B) 46

     (C) 48

     (D) 23

149. Haemophilia is which type of disease?

     (A) Sex-linked disease

     (B) Infectious disease

     (C) Deficiency disease

     (D) None of these

150. In Color Blindness, the patient cannot identify which colors?

     (A) Red and Blue

     (B) Red and Green

     (C) Blue and Yellow

     (D) Black and White