Class 12 Biology MCQ Chapter 16 Environmental Issues
Are you searching for Class 12 Biology MCQ Chapter 16 Environmental Issues English Medium? Then you are in the right place. This article provides important multiple-choice questions (MCQs) with answers from Chapter 16: Environmental Issues for AHSEC Higher Secondary students.
This chapter focuses on major environmental problems affecting the world today and the measures taken to solve them. Students will learn about air pollution, water pollution, soil pollution, solid waste management, greenhouse effect, global warming, ozone depletion, acid rain, deforestation, and environmental conservation. These topics are important for understanding the challenges faced by the environment and the role of humans in protecting natural resources.
All MCQs are prepared according to the latest AHSEC syllabus and examination pattern. Regular practice of these objective questions will help students revise important concepts, improve their understanding of environmental science, and prepare effectively for board examinations.
Whether you are preparing for class tests, model examinations, or the AHSEC Higher Secondary Final Examination, these MCQ solutions will help you strengthen your Biology preparation and score higher marks in examinations.
Unit X: Ecology
Environmental Issues
VSA & MCQ
I. Very Short Question-Answers
Q. What is pollution?
Ans: Pollution is the undesirable change in the physical, chemical or biological characteristics of the environment.
Q. Define air pollution.
Ans: Air pollution is the contamination of air by harmful substances.
Q. What is water pollution?
Ans: Water pollution is the contamination of water bodies by pollutants.
Q. What is soil pollution?
Ans: Soil pollution is the degradation of soil due to harmful chemicals and wastes.
Q. Define noise pollution.
Ans: Noise pollution is the presence of excessive unwanted sound in the environment.
Q. What are pollutants?
Ans: Pollutants are substances that cause pollution.
Q. Expand BOD.
Ans: BOD stands for Biochemical Oxygen Demand.
Q. What does high BOD indicate?
Ans: High BOD indicates high level of organic pollution in water.
Q. What is eutrophication?
Ans: Eutrophication is the excessive enrichment of water bodies with nutrients.
Q. Name the major greenhouse gas.
Ans: Carbon dioxide is the major greenhouse gas.
Q. What is greenhouse effect?
Ans: Greenhouse effect is the warming of Earth due to trapping of heat by greenhouse gases.
Q. Define global warming.
Ans: Global warming is the gradual increase in Earth’s average temperature.
Q. What is acid rain?
Ans: Acid rain is rain containing harmful acids formed from pollutants.
Q. Name the gases responsible for acid rain.
Ans: Sulphur dioxide and nitrogen oxides are responsible for acid rain.
Q. What is ozone depletion?
Ans: Ozone depletion is the thinning of ozone layer in the stratosphere.
Q. Name the chemicals mainly responsible for ozone depletion.
Ans: Chlorofluorocarbons (CFCs) are mainly responsible for ozone depletion.
Q. What is smog?
Ans: Smog is a mixture of smoke and fog.
Q. Define biomagnification.
Ans: Biomagnification is the increase in concentration of toxic substances at higher trophic levels.
Q. Which pesticide caused biomagnification in birds?
Ans: DDT caused biomagnification in birds.
Q. What is radioactive pollution?
Ans: Radioactive pollution is contamination caused by radioactive substances.
Q. What are electronic wastes?
Ans: Electronic wastes are discarded electronic devices and components.
Q. What is solid waste management?
Ans: Solid waste management is the collection, treatment and disposal of solid wastes.
Q. Define recycling.
Ans: Recycling is the process of converting waste materials into reusable materials.
Q. What is sewage?
Ans: Sewage is wastewater released from homes and industries.
Q. Name the disease caused by polluted water.
Ans: Cholera is caused by polluted water.
Q. What is algal bloom?
Ans: Algal bloom is rapid growth of algae in water bodies.
Q. Expand CPCB.
Ans: CPCB stands for Central Pollution Control Board.
Q. What is deforestation?
Ans: Deforestation is the large-scale cutting of forests.
Q. What is reforestation?
Ans: Reforestation is the replanting of trees in deforested areas.
Q. Name the protocol signed to control ozone depletion.
Ans: Montreal Protocol was signed to control ozone depletion.
II. Multiple Choice Questions (MCQs)
Q. Pollution means:
(a) Improvement of environment
(b) Natural conservation
(c) Undesirable environmental change
(d) Afforestation
Ans: (c) Undesirable environmental change
Q. BOD stands for:
(a) Biological Oxygen Demand
(b) Biochemical Oxygen Demand
(c) Basic Oxygen Demand
(d) Biotic Oxygen Demand
Ans: (b) Biochemical Oxygen Demand
Q. High BOD in water indicates:
(a) Clean water
(b) Low organic matter
(c) High pollution
(d) High oxygen level
Ans: (c) High pollution
Q. Greenhouse effect is mainly caused by:
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Helium
Ans: (c) Carbon dioxide
Q. The increase in Earth’s temperature is called:
(a) Acid rain
(b) Global warming
(c) Eutrophication
(d) Biomagnification
Ans: (b) Global warming
Q. Acid rain is mainly caused by:
(a) Oxygen and nitrogen
(b) Sulphur dioxide and nitrogen oxides
(c) Carbon dioxide only
(d) Methane only
Ans: (b) Sulphur dioxide and nitrogen oxides
Q. Ozone layer is present in:
(a) Troposphere
(b) Mesosphere
(c) Stratosphere
(d) Thermosphere
Ans: (c) Stratosphere
Q. Ozone depletion is mainly caused by:
(a) Carbon dioxide
(b) Sulphur dioxide
(c) Chlorofluorocarbons
(d) Oxygen
Ans: (c) Chlorofluorocarbons
Q. Smog is formed by:
(a) Smoke and fog
(b) Dust and water
(c) Carbon and oxygen
(d) Nitrogen and fog
Ans: (a) Smoke and fog
Q. Biomagnification refers to:
(a) Reduction of pollutants
(b) Increase of toxins along food chain
(c) Decrease in biodiversity
(d) Soil formation
Ans: (b) Increase of toxins along food chain
Q. Which pesticide is associated with biomagnification?
(a) Urea
(b) DDT
(c) Ammonia
(d) Methane
Ans: (b) DDT
Q. Excess nutrients in water cause:
(a) Acid rain
(b) Ozone depletion
(c) Eutrophication
(d) Desertification
Ans: (c) Eutrophication
Q. Algal bloom occurs due to:
(a) Nutrient enrichment
(b) Low temperature
(c) Soil erosion
(d) Deforestation
Ans: (a) Nutrient enrichment
Q. Noise pollution affects mainly:
(a) Hearing ability
(b) Photosynthesis
(c) Soil fertility
(d) Water quality
Ans: (a) Hearing ability
Q. Electronic wastes are called:
(a) Biowaste
(b) E-waste
(c) Sewage
(d) Sludge
Ans: (b) E-waste
Q. Recycling helps in:
(a) Increasing waste
(b) Conserving resources
(c) Pollution increase
(d) Ozone depletion
Ans: (b) Conserving resources
Q. Sewage mainly contains:
(a) Pure water
(b) Domestic wastewater
(c) Oxygen only
(d) Minerals only
Ans: (b) Domestic wastewater
Q. Which disease spreads through polluted water?
(a) Cholera
(b) Malaria
(c) Tuberculosis
(d) Influenza
Ans: (a) Cholera
Q. The protocol related to ozone conservation is:
(a) Kyoto Protocol
(b) Montreal Protocol
(c) Geneva Protocol
(d) Rio Protocol
Ans: (b) Montreal Protocol
Q. Deforestation results in:
(a) Increase in biodiversity
(b) Soil erosion
(c) Increase in rainfall
(d) Ozone formation
Ans: (b) Soil erosion
Q. Reforestation means:
(a) Cutting forests
(b) Planting trees again
(c) Mining
(d) Industrialization
Ans: (b) Planting trees again
Q. Which gas is known as greenhouse gas?
(a) Oxygen
(b) Hydrogen
(c) Carbon dioxide
(d) Neon
Ans: (c) Carbon dioxide
Q. Acid rain damages:
(a) Buildings and plants
(b) Stars
(c) Moonlight
(d) Clouds only
Ans: (a) Buildings and plants
Q. CPCB is related to:
(a) Pollution control
(b) Space research
(c) Banking
(d) Agriculture only
Ans: (a) Pollution control
Q. Which of the following is biodegradable?
(a) Plastic
(b) Glass
(c) Vegetable waste
(d) Metal
Ans: (c) Vegetable waste
Q. Non-biodegradable waste includes:
(a) Leaves
(b) Plastic
(c) Fruits
(d) Paper
Ans: (b) Plastic
Q. The thinning of ozone layer increases:
(a) Visible light
(b) Infrared rays
(c) UV radiation reaching Earth
(d) Rainfall
Ans: (c) UV radiation reaching Earth
Q. Greenhouse effect ultimately leads to:
(a) Cooling of Earth
(b) Global warming
(c) Acid rain only
(d) Soil formation
Ans: (b) Global warming
Q. Which one is a renewable resource?
(a) Coal
(b) Petroleum
(c) Solar energy
(d) Natural gas
Ans: (c) Solar energy
Q. Which of the following causes radioactive pollution?
(a) Nuclear waste
(b) Organic manure
(c) Compost
(d) Irrigation
Ans: (a) Nuclear waste
Q. Assertion (A): High BOD indicates polluted water.
Reason (R): Organic wastes consume dissolved oxygen during decomposition.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (b) Both A and R are true, but R is not the correct explanation of A
Q. Assertion (A): Greenhouse gases increase global temperature.
Reason (R): They trap heat radiated from Earth’s surface.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (d) A is false, but R is true
Q. Assertion (A): Biomagnification affects higher trophic levels more severely.
Reason (R): Toxic substances accumulate progressively along food chains.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (c) A is true, but R is false
Q. Assertion (A): Montreal Protocol aims to protect ozone layer.
Reason (R): It controls the use of chlorofluorocarbons.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (a) Both A and R are true and R is the correct explanation of A
Q. Assertion (A): Recycling reduces environmental pollution.
Reason (R): Recycling decreases accumulation of waste materials.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (b) Both A and R are true, but R is not the correct explanation of A
Q. Assertion (A): Ozone depletion increases UV radiation reaching Earth.
Reason (R): Ozone absorbs harmful ultraviolet rays.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (d) A is false, but R is true
Q. Assertion (A): Eutrophication decreases dissolved oxygen in water bodies.
Reason (R): Excessive algal growth increases decomposition activity.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Ans: (c) A is true, but R is false.
